Why does alcohol cause the hemolysis of RBC in a large proportion?

Why does alcohol cause the hemolysis of RBC in a large proportion?

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I had today an experiment that we put 95% alcohol to the blood which made it completely transparent so hemolysis must have occurred. I started to think about the reasons.

I think that this is because alcohol dissolved the lipid membrane of cells outside of the cell. Alcohol molecule is also very small. I think that I can go through the bilayer too. So I started to think that the other possible reason was that alcohol went inside the cell so caused

  • dissolution of the membrane from the inner side
  • increase in the volume of the cell so bursting

What are the main reasons why Alcohol cause hemolysis to the red blood cell?

Well, it turns out the situation is more complex. I had assumed the answer was what rwst suggests or something to do with osmotic pressure. It seems that we don't really know that well.

In a paper from 1991, Chi and Wu suggest the following possible mechanisms :

  1. Membrane fusion during the shedding of exovesicles might produce a transient decrease of the permeability barrier.

  2. Increase of lipid dynamics by the alcohol could decrease the packing of the bilayer. The membrane barrier behaves like a soft polymer, which can sieve solutes. The meshes in the polymer might become larger if its packing density is reduced.

  3. Lateral phase separation of lipids could induce packing defects in the lipid domain. This has been observed for long chain alcohols and postulated to be responsible for the increase of membrane permeability by amphiphiles.

  4. Increase of the dielectric constant of the membrane by the alcohol would also increase the partition of hydrophilic solutes into the membranes. Such an increase has been postulated to be responsible for the increase of the permeability by aliphatic alcohols.

  5. Modification of the intrinsic membrane domain might follow modification of the membrane skeleton by the alcohol. Accordingly, aggregation of intrinsic proteins might cause membrane modification mentioned under point 2 to 4.

The authors state that it is not possible to decide between the various possibilities, but they seem to prefer point 5:

Although it is not possible to decide between the various possibilities from the present data, we showed that the release of membrane fragments from ethanol-treated RBC was not a requirement for the creation of membrane pores since it occurred at a time much later than the detection of K ÷ leakage. In addition, we found that changes of membane rheological properties preceded the permeability increase. These properties have been related to the membrane skeletal protein spectrin. Moreover, ethanol has been shown to affect the skeleton. The processes leading to the formation of pores in ethanol-treated RBC may thus relate to a deranged cytoskeletal network, followed by the aforementioned alteration of membrane properties.

The plot thickens, apparently, low concentrations of alcohol protect erythrocytes from hemolysis while higher concentrations can cause it. The following are extracts from Tyulina et al:

The seeming paradox between the direct haemolytic effect of ethanol on erythrocytes (Fig. 1) and the stabilizing effect of ethanol on erythrocytes undergoing NaOCl-induced haemolysis (Fig. 2) could be explained by the relatively small destabilizing effect of ethanol which is observed (<1% haemolysis) over 16 h. This effect would be negligible in the short time period (generally <10 min) assay for NaOCl-induced haemolysis where 100% of the cells are haemolysed. An alternative explanation for this paradox is that the mechanisms of haemolysis induced by ethanol and NaOCl are different.

It therefore appears that ethanol does not induce significant oxidative stress in the human erythrocyte, and these data are in agreement with previous studies (Seeman et al., 1971), in which it was found that low ethanol concentrations could protect erythrocytes against haemolysis. Although the mechanism for this protective effect is unknown, it has previously been suggested (Halliwell and Gutteridge, 1999) that ethanol can serve as a hydrogen donor in the elimination of the hydroxyl radical with formation of water and the 2-hydroxyethyl radical.

The authors then state (emphasis mine):

In summary, we conclude that the damage to erythrocytes which occurs on in vitro exposure to ethanol may be caused, at least in part, by unmetabolized ethanol directly, rather than by the oxidation of ethanol to acetaldehyde or its conversion to FAEE.

I would guess this "direct effect" is something very much like what rwst suggested but the fact that the authors, who clearly work in this field, do not say so makes me think that the situation is more complex.

So, in conclusion, the exact details of alcohol's hemolytic properties don't seem to be understood in great detail. Admittedly, neither of these articles is very recent, if anyone can find a more up to date account I would love to read it.


Chi LM, Wu WG. Mechanism of hemolysis of red blood cell mediated by ethanol. Biochim Biophys Acta. 1991 Feb 11;1062(1):46-50.

Tyulina OV, Prokopieva VD, Dodd RD, Hawkins JR, Clay SW, Wilson DO, Boldyrev AA, Johnson P. In vitro effects of ethanol, acetaldehyde and fatty acid ethyl esters on human erythrocytes. Alcohol Alcohol. 2002 Mar-Apr;37(2):179-86.

Trandum C, Westh P, Jørgensen K, Mouritsen OG. Association of ethanol with lipid membranes containing cholesterol, sphingomyelin and ganglioside: a titration calorimetry study. Biochim Biophys Acta. 1999 Aug 20;1420(1-2):179-88.

Ethanol, in less than 50% concentration, emulgates lipids and, through interference with hydrogen bonds, leads to conformational changes in proteins. Higher concentrations lead to denaturation of proteins and osmolysis of cells through small defects, so they finally burst, as ethanol forces a concentration equilibrium. This is why it's a good desinfection substance. But you could use any other small molecule polar solvent.

Your kidneys filter harmful substances from your blood. One of these substances is alcohol. Alcohol can cause changes in the function of the kidneys and make them less able to filter your blood. In addition to filtering blood, your kidneys do many other important jobs. One of these jobs is keeping the right amount of water in your body. Alcohol affects the ability of your kidneys to do this. When alcohol dehydrates (dries out) the body, the drying effect can affect the normal function of cells and organs, including the kidneys.

Too much alcohol can also affect your blood pressure. People who drink too much are more likely to have high blood pressure. And medications for high blood pressure can be affected by alcohol. High blood pressure is a common cause of kidney disease. More than two drinks a day can increase your chance of having high blood pressure.

Chronic drinking can also cause liver disease. This adds to the kidney's job. The rate of blood flow to your kidneys is usually kept at a certain level, so that your kidneys can filter your blood well. Liver disease impairs this important balancing act. In fact, most patients in the United States who have both liver disease and associated kidney dysfunction are alcohol dependent.


Malaria Edit

Primaquine is primarily used to prevent relapse of malaria due to Plasmodium vivax and Plasmodium ovale. [8] It eliminates hypnozoites, the dormant liver form of the parasite, [9] after the organisms have been cleared from the bloodstream. [8] If primaquine is not administered to patients with proven P. vivax or P. ovale infection, a very high likelihood of relapse exists for weeks or months (sometimes years). [8] Use in combination with quinine or chloroquine each of which is very effective at clearing P. vivax from blood, improves outcomes they appear to also potentiate the action of primaquine. [10]

As of 2016, the US Centers for Disease Control and Prevention recommended the use of primaquine for primary prophylaxis prior to travel to areas with a high incidence of P. vivax, and for terminal prophylaxis (anti-relapse therapy) after travel. [4]

A single dose of primaquine has rapid and potent ability to kill gametocytes (stage V) of P. falciparum and P. vivax in blood it also kills asexual trophozoites of P. vivax in blood, but not of P. falciparum. [10] Because of its action against gametocytes, the WHO recommends it for use in reducing transmission to control P. falciparum infections. [11]

Pneumocystis pneumonia Edit

Primaquine is also used in the treatment of Pneumocystis pneumonia (PCP), a fungal infection commonly occurring in people with AIDS and, more rarely, in those taking immunosuppressive drugs. To treat PCP effectively, it is usually combined with clindamycin. [3]

Special populations Edit

Primaquine has not been studied extensively in people 65 and older so it is not known if dosing should be adjusted for this population. [12]

Primaquine should not be administered to anyone with G6PD deficiency because a severe reaction can occur, resulting in hemolytic anemia. [4] However, the WHO has recommended that a single dose of primaquine (0.25 mg/kg) is safe to give even in individuals with G6PD deficiency, for the purpose of preventing transmission of P. falciparum malaria. [11]

Primaquine is contraindicated in pregnancy, because the glucose-6-phosphate dehydrogenase status of the fetus would be unknown. [4]

Primaquine overdose can cause a dangerous reduction in various blood cell counts, and therefore should be avoided in people at risk for agranulocytosis, which include people with conditions such as rheumatoid arthritis and lupus erythematosus, and those taking concurrent medications that also decrease blood cell counts. [12]

Common side effects of primaquine administration include nausea, vomiting, and stomach cramps. [4] [12]

In persons with cytochrome b5 reductase deficiency, primaquine causes methemoglobinemia, a condition in which the blood carries less oxygen that it does normally. [12]

Overdosing can reduce the number of function of various kinds of blood cells, including loss of red blood cells, methemoglobinemia, and loss of white blood cells. [12]

Persons with glucose-6-phosphate dehydrogenase deficiency (G6PD) may develop hemolytic anemia from primaquine. [13]

Mechanism of action Edit

Primaquine is lethal to P. vivax and P. ovale in the liver stage, and also to P. vivax in the blood stage through its ability to do oxidative damage to the cell. However, the exact mechanism of action is not fully understood. [6]

Pharmacokinetics Edit

Primaquine is well-absorbed in the gut and extensively distributed in the body without accumulating in red blood cells. Administration of primaquine with food or grapefruit juice increases its oral bioavailibity. [14] In blood, about 20% of circulating primaquine is protein-bound, with preferential binding to the acute phase protein orosomucoid. With a half-life on the order of 6 hours, it is quickly metabolized by liver enzymes to carboxyprimaquine, which does not have anti-malarial activity. Renal excretion of the parent drug is less than 4%. [6] [15]

Primaquine is an analog of pamaquine which was the first drug of the 8-aminoquinoline class tafenoquine is another such drug. [10]

Primaquine was first made by Robert Elderfield of Columbia University in the 1940s as part of a coordinated effort led by the Office of Scientific Research and Development in World War II to develop anti-malarial drugs to protect and treat soldiers fighting in the Pacific theater. [10] [16]

It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system. [7]

It is a generic drug and is available under many brand names worldwide, including Jasoprim, Malirid, Neo-Quipenyl, Pimaquin, Pmq, Primachina, Primacin, Primaquina, Primaquine, Primaquine diphosphate, Primaquine Phosphate, and Remaquin. [17]

Primaquine has been studied in animal models of Chagas disease and was about four times as effective as the standard of care, nifurtimox. [3]

Hormonal Control of RBC Release

Causes of Low HCT and HGB

A hormone called erythropoietin (EPO), produced by the kidneys, controls the rate of RBC production and release from the bone marrow. When EPO levels rise, more immature RBCs are released from the bone marrow, resulting in polychromasia. EPO is usually released in response to anemia (a lowered number of RBCs in the blood), so anemia should be considered a cause of polychromasia.

  • A hormone called erythropoietin (EPO), produced by the kidneys, controls the rate of RBC production and release from the bone marrow.
  • When EPO levels rise, more immature RBCs are released from the bone marrow, resulting in polychromasia.

ELECTROPHORESIS | Micellar Electrokinetic Chromatography

Anionic Surfactants

Anionic surfactant systems are preferred in MEKC because the electrophoretic migration of the micelles is in the opposite direction to the electroosmotic flow, and the micelles do not interact with the negatively charged walls of the fused silica capillaries. Anionic surfactants with alkyl chain and polar group, such as sodium decyl sulfate, sodium N-lauroyl-N-methyltaurate, sodium tetradecyl sulfate, and especially sodium dodecyl sulfate (SDS) are the most widely used. Simultaneous separation of neutral and positively charged compounds is not possible at low pH because the EOF is too slow to carry the micelles to the cathode.

Most studies with anionic surfactants have been carried out under neutral or basic conditions. The most frequently used anionic surfactant, SDS, forms relatively spherical micelles with hydrophobic tail groups oriented towards the centre and charged head groups along the outer surface. The surfaces of SDS micelles possess a large net negative charge, giving them a large electrophoretic mobility toward the anode.

Another group of anionic surfactants, which has been widely used in separations of both neutral and ionic analytes, is bile salts. Bile salts have a hydroxyl-substituted steroidal backbone with hydrophilic and hydrophobic faces and they form helical micelles. Bile salts have a lower solubilizing effect on hydrophobic compounds than does SDS.

I. Decrease in Platelets

A decrease in platelets can be innate or acquired (more often). Acquired forms are caused by factors that have affected the bone marrow. These factors may include the following:

  • Anemia – due to lack of folic acid (vitamin B9) or vitamin B12 resulting to a reduction in the production of blood cells.
  • Alcohol – thrombocytopenia is often observed in heavy drinkers, especially in individuals with poor diet practices.
  • Leukemia
  • Viral infection
  • Toxic chemicals
  • Ionizing radiation
  • Cytostatics
  • Tumor metastasis
  • Intake of certain medications

Increased platelet degradation and consumption

In some cases of thrombocytopenia, platelets are decreased because of destruction or increased in their consumption. The normal production rate of the bone marrow cannot make up for the loss, which is why a fall in the number of platelets develop. This abnormal condition can be divided into immune and non-immune forms.

In non-immune thrombocytopenia, this group of abnormal condition includes hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), and thrombocytopenia caused by disseminated intravascular coagulopathy.

HUS is characterized by the triad of acute renal failure, hemolytic anemia, and thrombocytopenia. The medical condition may display acute febrile symptoms with diarrhea, or upper respiratory tract infection. In children, this rare disorder is characteristic to early childhood (younger than 4 years old). The most common factor that can lead to the development of HUS is an infection with E.coli serotype O157: H7, although other bacterial and viral pathogens may also lead to the syndrome.

TTP is a disease characterized by a pentad of symptoms: thrombocytopenia, hemolytic anemia, renal failure, fever, and neurologic disorders. The disease is due to a reduction in the formation of enzyme ADAMTS13 which is important in the biology of von Willebrand factor, significant in coagulation. There will be increased production of blood clots in small blood vessels. The damage is usually caused by the formation of auto-antibodies against the enzyme which may be acute but a life-threatening condition.

Some other reasons for increased platelet degradation

  • Certain drugs, alcohol, bacteria, viruses that directly decompose platelets.
  • Immune system abnormal functioning, mistakenly identifying normal cells, forming antibodies to destroy them. The creation of antibodies may occur after transfusion of blood components or platelets. Destruction is also possible due to autoimmune diseases or intake of certain medications.
  • Attributing to the abnormal formation of numerous blood clots in the circulation, there can be increased platelet consumption. This may happen due to severe bacterial or viral infection, a serious complication of pregnancy, drugs, or tissue damage.
  • During pregnancy, platelet count may be slightly reduced.

The “capture” of platelets in the spleen

The spleen plays an important role in the body’s defense against infection. However, this place of storage for the blood cells can be impaired for a number of reasons. The damage can result to large amounts of platelet accumulation in the spleen.

Normally, stored platelets in the spleen amount to only a third of all platelets in the body. But with an enlarged spleen, it can reach up to 90% of all platelets, which causes a relative decrease in the number of platelets circulating in the bloodstream. The life span of platelets remains normal still.

Thrombocytopenia due to splenomegaly doesn’t come with an increased risk of bleeding. But often, hypersplenism associated with liver cirrhosis, which is associated with disorders on normal coagulation, predisposes the patient to be at increased risk of bleeding.

Blood Sludging

Causes of Low Blood Oxygen Levels

Blood sludging is the clinical term used to describe the phenomenon between alcohol and your red blood cells, which, in turn, impacts your body's ability to absorb oxygen. Once alcohol has entered your bloodstream, it causes your red blood cells to clump together. The clumping makes it so that the small blood vessels become blocked or plugged. As a result, the tissues and organs in your body are unable to receive oxygen from the blood. Without oxygen, cells, tissues and organs cannot function properly.

  • Blood sludging is the clinical term used to describe the phenomenon between alcohol and your red blood cells, which, in turn, impacts your body's ability to absorb oxygen.
  • As a result, the tissues and organs in your body are unable to receive oxygen from the blood.

Why does alcohol cause the hemolysis of RBC in a large proportion? - Biology

Red blood cells (RBCs), also called erythrocytes, are cells that circulate in the blood and carry oxygen throughout the body. The RBC count totals the number of red blood cells that are present in your sample of blood. It is one test among several that is included in a complete blood count (CBC) and is often used in the general evaluation of a person's health.

Blood is made up of a few different types of cells suspended in fluid called plasma. In addition to RBCs, there are white blood cells (WBCs) and platelets. These cells are produced in the bone marrow and are released into the bloodstream as they mature. RBCs typically make up about 40% of the blood volume. RBCs contain hemoglobin, a protein that binds to oxygen and enables RBCs to carry oxygen from the lungs to the tissues and organs of the body. RBCs also help transport a small portion of carbon dioxide, a waste product of cell metabolism, from those tissues and organs back to the lungs, where it is expelled.

The typical lifespan of an RBC is 120 days. Thus the bone marrow must continually produce new RBCs to replace those that age and degrade or are lost through bleeding. A number of conditions can affect RBC production and some conditions may result in significant bleeding. Other disorders may affect the lifespan of RBCs in circulation, especially if the RBCs are deformed due to an inherited or acquired defect or abnormality. These conditions may lead to a rise or drop in the RBC count. Changes in the RBC count usually mirror changes in other RBC tests, including the hematocrit and hemoglobin level.

  • If RBCs are lost or destroyed faster than they can be replaced, if bone marrow production is disrupted, or if the RBCs produced do not function normally, or do not contain enough hemoglobin, then you may develop anemia, which affects the amount of oxygen reaching tissues.
  • If too many RBCs are produced and released, then you can develop polycythemia. This can cause thicker blood, decreased blood flow and related problems, such as headache, dizziness, problems with vision, and even excessive clotting or heart attack.

A red blood cell (RBC) count is typically ordered as part of a complete blood count (CBC) and may be used as part of a health checkup to screen for a variety of conditions. This test may also be used to help diagnose and/or monitor a number of diseases that affect the production or lifespan of red blood cells.

An RBC count is ordered as a part of the complete blood count (CBC), often as part of a routine physical or as part of a pre-surgical workup. A CBC may be ordered when you have signs and symptoms suggesting a disease that might affect red blood cell production. Some common signs and symptoms associated with anemia that generally lead to a healthcare practitioner ordering a CBC are:

Some signs and symptoms that may appear with a high RBC count include:

A CBC may also be performed on a regular basis to monitor people who have been diagnosed with conditions such as:

Since an RBC count is performed as part of a complete blood count (CBC), results from other components are taken into consideration. A rise or drop in the RBC count must be interpreted in conjunction with other tests, such as hemoglobin, hematocrit, reticulocyte count, and/or red blood cell indices.

The following table summarizes what results may mean.

Men: 4.5-5.9 x 10 6 /microliter

Women: 4.1-5.1 x 10 6 microliter

    or chronic bleeding
  • RBC destruction (e.g., hemolytic anemia, etc.)
  • Nutritional deficiency (e.g., iron deficiency, vitamin B12 or folate deficiency) or damage
  • Chronic inflammatory disease

from Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed.
McPherson R, Pincus M, eds. Philadelphia, PA: Elsevier Saunders 2011.

Note: Conventional Units are typically used for reporting results in U.S. labs
SI Units are used to report lab results outside of the U.S.

Some causes of a low RBC count (anemia) include:

  • Trauma that leads to loss of blood
  • Conditions that cause red blood cells to be destroyed, such as hemolytic anemia caused by autoimmunity or defects in the red cell itself the defects could be a hemoglobinopathy (e.g., sickle cell anemia), thalassemia, an abnormality in the RBC membrane (e.g., hereditary spherocytosis), or enzyme defect (e.g., G6PD deficiency).
  • Sudden (acute) or chronic bleeding from the digestive tract (e.g., ulcers, polyps, colon cancer) or other sites, such as the bladder or uterus (in women, heavy menstrual bleeding, for example)
  • Nutritional deficiency such as iron deficiency or vitamin B12 or folate deficiency
  • Bone marrow damage (e.g., toxin, radiation or chemotherapy, infection, drugs) such as leukemia, multiple myeloma, myelodysplastic syndrome, or lymphoma or other cancers that spread to the bone marrow
  • Chronic inflammatory disease or condition
  • Kidney failure—severe and chronic kidney diseases lead to decreased production of erythropoietin, a hormone produced by the kidneys that promotes RBC production by the bone marrow.

Some causes of a high RBC count (polycythemia) include:

    —as the volume of fluid in the blood drops, the count of RBCs per volume of fluid artificially rises. —if someone is unable to breathe in and absorb sufficient oxygen, the body tries to compensate by producing more red blood cells. —with this condition, the heart is not able to pump blood efficiently, resulting in a decreased amount of oxygen getting to tissues. The body tries to compensate by producing more red blood cells.
  • Kidney tumor that produces excess erythropoietin
  • Smoking
  • Genetic causes (altered oxygen sensing, abnormality in hemoglobin oxygen release)
  • Polycythemia vera—a rare disease in which the body produces too many RBCs

Your RBC count is interpreted by your healthcare practitioner within the context of other tests that you have had done as well as other factors, such as your medical history. A single result that is slightly high or low may or may not have medical significance. There are several reasons why a test result may differ on different days and why it may fall outside a designated reference range.

  • Biological variability (different results in the same person at different times): If you have the same test done on several different occasions, there's a good chance that one result will fall outside a reference range even though you are in good health. For biological reasons, your values can vary from day to day.
  • Individual variability (differences in results between different people): References ranges are usually established by collecting results from a large population and determining from the data an expected average result and expected differences from that average (standard deviation). There are individuals who are healthy but whose tests results, which are normal for them, do not always fall within the expected range of the overall population.

A test value that falls outside of the established reference range supplied by the laboratory may mean nothing significant. Generally, this is the case when the test value is only slightly higher or lower than the reference range and this is why a healthcare practitioner may repeat a test on you and why they may look at results from prior times when you had the same test performed.

However, a result outside the range may indicate a problem and warrant further investigation. Your healthcare provider will consider your medical history, physical exam, and other relevant factors to determine whether a result that falls outside of the reference range means something significant for you. For more, read the articles on Reference Ranges and What They Mean.

An RBC count can be used to detect a problem with red blood cell production and/or lifespan, but it cannot determine the underlying cause. In addition to the full CBC, some other tests may be performed at the same time or as follow up to help establish a diagnosis. Examples include:

    —a laboratory professional examines the blood under the microscope to confirm results of a CBC and/or to look abnormal blood cells —determines the number of young (immature) red blood cells —iron is important in the production of red blood cells —these vitamins are also important for red blood cell production
  • In more severe conditions, a bone marrow aspiration and biopsy—usually done by a pathologist to help detect abnormalities in the bone marrow and determine the cause of low or high blood cell counts or abnormal blood cells

First, a healthcare practitioner must determine the cause of someone's abnormal RBC count so the appropriate treatment can be prescribed. For some anemias, treatment may include a dietary supplement or a change in diet to include nutritional foods. In some instances, it may only require a change in the person's current medication. For more severe cases, treatment may involve transfusion with blood from a donor. For some, prescribing a drug to stimulate red cell production in the bone marrow may be required, especially for people who have received chemotherapy or radiation treatments.

Maybe. Some healthcare practitioners' offices are equipped with laboratory instruments and staffed by trained laboratorians who are able to perform this test.

Yes, to the extent that if you eat a well-balanced diet, you can prevent anemia due to a lack of iron, vitamin B12, or folate in the foods you eat. Sometimes use of a supplement is recommended if you are at risk of a vitamin deficiency. However, the most common cause of vitamin B12 deficiency is malabsorption, and the most common cause of iron deficiency is bleeding. These conditions and other RBC problems that are caused by diseases other than nutritional deficiencies will not be corrected by diet.

Fatigue and weakness may indicate a low or high RBC count. Fainting, pallor, shortness of breath, dizziness, and/or altered mental status can also indicate a low RBC count. Disturbed vision, headache, and flushing may be present with increased numbers of RBCs.

A recent blood transfusion can affect results of an RBC count.

Alteration of the number of RBCs is often temporary and can be easily corrected and/or returned to normal levels by treating and resolving the underlying condition.

During pregnancy, body fluids tend to accumulate, thus decreasing the RBC count in relation to fluid volume.

Living at high altitudes causes an increase in RBC count this is the body's response to the decreased oxygen available at these heights.

Women tend to have slightly lower RBC counts than men.

You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab's website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called "normal" values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

For more information, please read the article Reference Ranges and What They Mean.

The reference ranges 1 provided here represent a theoretical guideline that should not be used to interpret your test results. Some variation is likely between these numbers and the reference range reported by the lab that ran your test. Please consult your healthcare provider.

Age Conventional Units 2 SI Units 3
0-18 years Not available due to wide variability. See child's lab report for reference range.
Adult male 4.5-5.9 x 10 6 /microliter 4.5-5.9 x 10 12 /L
Adult female 4.1-5.1 x 10 6 microliter 4.1-5.1 x 10 12 /L

1 from Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. McPherson R, Pincus M, eds. Philadelphia, PA: Elsevier Saunders 2011.

2 Conventional Units are typically used for reporting results in U.S. labs

3 SI Units are used to report lab results outside of the U.S.

LOINC Observation Identifiers Names and Codes (LOINC®) is the international standard for identifying health measurements, observations, and documents. It provides a common language to unambiguously identify things you can measure or observe that enables the exchange and aggregation of clinical results for care delivery, outcomes management, and research. Learn More.

Listed in the table below are the LOINC with links to the LOINC detail pages. Please note when you click on the hyperlinked code, you are leaving Lab Tests Online and accessing

LOINC LOINC Display Name
26453-1 RBC (Bld) [#/Vol]
789-8 RBC Auto (Bld) [#/Vol]
790-6 RBC Manual cnt (Bld) [#/Vol]

On This Site

Elsewhere On The Web

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Harmening, D. Clinical Hematology and Fundamentals of Hemostasis, Fifth Edition, F.A. Davis Company, Philadelphia, 2009, Chapter 3.

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Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson R, Pincus M, eds. Philadelphia, PA: Saunders Elsevier: 2007, Chap 31.

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To find out if hemolysis has taken place, you should streak for isolation on the blood agar plate. The medium is incubated overnight and will be inspected for any signs of hemolysis.

If the color of the medium is altered as characterized by a dark or discolored medium, it means that the organism has undergone alpha-hemolysis. On the other hand, the hemolysis is beta-hemolytic if the medium is cleared under growth. If the color of the medium didn’t change, it means that the medium constitutes gamma-hemolysis. (8, 9, and 10)

Mystery solved: How sickle hemoglobin protects against malaria

The latest issue of the journal Cell carries an article that is likely to help solve one of the long-standing mysteries of biomedicine. In a study that challenges currently held views, researchers at the Instituto Gulbenkian de Ciência (IGC), in Portugal, unravel the molecular mechanism whereby sickle cell hemoglobin confers a survival advantage against malaria, the disease caused by Plasmodium infection. These findings, by the research team lead by Miguel P. Soares, open the way to new therapeutic interventions against malaria, a disease that continues to inflict tremendous medical, social and economic burdens to a large proportion of the human population.

Sickle cell anemia is a blood disease in which red blood cells reveal an abnormal crescent (or sickle) shape when observed under a conventional microscope. It is an inherited disorder -- the first ever to be attributed to a specific genetic modification (mutation), in 1949 by Linus Pauling (two-times Nobel laureate, for Chemistry in 1954, and Peace, in 1962). The cause of sickle cell anemia was attributed unequivocally to a single base substitution in the DNA sequence of the gene encoding the beta chain of hemoglobin, the protein that carries oxygen in red blood cells.

Only those individual that inherit two copies of the sickle mutation (one from their mother and the other from their father) develop sickle cell anemia. If untreated, these individuals have a shorter than normal life expectancy and as such it would be expected that this mutation would be rare in human populations. This is however, far from being the case. Observations made during the mid-20th century and building on Pauling's findings, revealed that the sickle mutation is, in fact, highly, selected in populations from areas of the world were malaria is very frequent, with sometimes 10-40% of the population carrying this mutation.

Individuals carrying just one copy of the sickle mutation (inherited from either the father or mother) were known not to develop sickle cell anemia, leading rather normal lives. However, it was found that these same individuals, said to carry the sickle cell trait, were in fact highly protected against malaria, thus explaining the high prevalence of this mutation in geographical areas where malaria is endemic.

These findings lead to the widespread believe in the medical community that understanding the mechanism whereby sickle cell trait protects against malaria would provide critical insight into developing treatment or a possible cure for this devastating disease, responsible for over a million premature deaths in sub-Saharan Africa. Despite several decades of research, the mechanism underlying this protective effect remained elusive. Until now.

Several studies suggested that, in one way or another, sickle hemoglobin might get in the way of the Plasmodium parasite infecting red blood cells, reducing the number of parasites that actually infect the host and thus conferring some protection against the disease. The IGC team's results challenge this explanation.

In painstakingly detailed work, Ana Ferreira, a post-doctoral researcher in Miguel Soares' laboratory, demonstrated that mice obtained from Prof. Yves Beuzard's laboratory, that had been genetically engineered to produce one copy of sickle hemoglobin similar to sickle cell trait, do not succumb to cerebral malaria, thus reproducing what happens in humans.

When Prof. Ingo Bechman observed the brains of these mice he confirmed that the lesions associated with the development of cerebral malaria where absent, despite the presence of the parasite.

Ana Ferreira went on to show that the protection afforded by sickle hemoglobin in these mice, acts without interfering directly with the parasite's ability to infect the host red blood cells. As Miguel Soares describes it, "sickle hemoglobin makes the host tolerant to the parasite."

Through a series of genetic experiments, Ana Ferreira was able to show that the main player in this protective effect is heme oxygenase-1 (HO-1), an enzyme whose expression is strongly induced by sickle hemoglobin. This enzyme, that produces the gas carbon monoxide, had been previously shown by the laboratory of Miguel Soares to confer protection against cerebral malaria. In the process of dissecting further this mechanism of protection Ana Ferreira demonstrated that when produced in response to sickle hemoglobin the same gas, carbon monoxide, protected the infected host from succumbing to cerebral malaria without interfering with the life cycle of the parasite inside its red blood cells.

Miguel Soares and his team believe that the mechanism they have identified for sickle cell trait may be a general mechanism acting in other red blood cell genetic diseases that are also know to protect against malaria in human populations: "Due to its protective effect against malaria, the sickle mutation may have been naturally selected in sub-Saharan Africa, where malaria is endemic and one of the major causes of death. Similarly, other clinically silent mutations may have been selected throughout evolution, for their ability to provide survival advantage against Plasmodium infection."

This research was carried out the at the IGC in collaboration with the Team of Prof. Yves Beuzard (Université Paris VII et XI, France), an expert in sickle cell anemia, and Prof. Ingo Bechman an expert in neuropathological diseases (Institute of Anatomy, University of Leipzig, Germany). Other IGC researchers involved in this study are Ivo Marguti, Viktória Jeney, Ângelo Chora, Nuno Palha and Sofia Rebelo. This project was funded by Fundação para a Ciência e a Tecnologia (Portugal), GEMI Fund Linde Healthcare and the European Commission's Framework Programme 7.

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