• Blood cell counts
• A brief explanation of blood cell counts
• Blood cell counts table
• Blood cell counts references

Blood cell counts

A blood cell count may be taken when an infection or anemia is suspected. Both can indirectly affect hair growth and promote hair loss. Chronic infection leads to a general run-down feeling, reduced hormone activity and a lack of nutrients. These factors may lead to an increase in hair loss - usually a type of telogen effluvium. Anemia is an indicator of low iron and ferritin levels which have also been associated with the development of telogen effluvium. The reference table below gives an idea of the typical reference values for each aspect of a comprehensive blood test for a normal, healthy individual. Note that reference values are slightly different from laboratory to laboratory as the is no standardization of testing between the laboratories. However, the laboratory reference values below should be applicable in most instances.

Testing laboratories establish these reference range values for most blood tests so that 95% of healthy patients fall within that 'normal' range. This means that 5% of healthy patients fall outside of the "reference" range, even though there may be nothing wrong with them at all! Therefore, an "abnormal" blood test result does not necessarily mean that there is something wrong with you. Many non-illness related factors may have an impact on your blood test results. These include such things as the nature and quantity of food intake in the 24 hours preceding the test, race, sex, stress, menstrual cycle, physical exercise in the hours before testing, collection and/or handling of the specimen, non-prescription drugs (aspirin, cold medications, vitamins, etc.), prescription drugs, alcohol intake, and the quality of the sleep that you got on the night before the test, among other things.

A brief explanation of blood cell counts

Red Blood Cells (RBC) - Also called erythrocytes, RBCs are responsible for delivering oxygen throughout the body. Anemia, a condition generally defined as a decreased number of red Blood cells, can be caused by certain anti-HIV drugs or be a sign of an underlying illness. Women of child-bearing age may also experience anemia as a result of Blood loss from their menstrual periods. One of the most common physical symptoms of anemia is fatigue.

Hemoglobin (HGB) - Hemoglobin is a protein that enables the RBCs to distribute oxygen throughout the body. A hemoglobin test is done when a person is ill or during a general physical examination. Good health requires an adequate amount of hemoglobin. The amount of oxygen in the body tissues depends on how much hemoglobin is in the red cells. Without enough hemoglobin, the tissues lack oxygen, and the heart and lungs must work harder to try to compensate. If the test indicates a "less than" or "greater than" normal amount of hemoglobin, the cause of the decrease or increase must be discovered. A low hemoglobin usually means the person has anemia. Anemia results from conditions that decrease the number or size of red cells, such as excessive bleeding, a dietary deficiency, destruction of cells because of a transfusion reaction or mechanical heart valve, or an abnormally formed hemoglobin. A high hemoglobin may be caused by polycythemia vera, a disease in which too many red blood cells are made. Hemoglobin levels also help determine if a person needs a Blood transfusion.

Neutrophils - An excess of neutrophils suggests problems with hematologic malignancy (leukemia, myelofibrosis) versus reactive leukocytosis, including "leukemoid reactions." Laboratory tests of this problem may include expert review of the peripheral smear, leukocyte alkaline phosphatase, and cytogenetic analysis of peripheral blood or marrow granulocytes. Neutropenia (excess numbers of neutrophils) may be found in certain infections, including typhoid fever, brucellosis, viral illnesses, rickettsioses, and malaria. Other causes include aplastic anemia, aleukemic acute leukemias, thyroid disorders, hypopitituitarism, cirrhosis, and Chediak-Higashi syndrome.

Lymphocytes - An excess of lymphocytes is seen in infectious mononucleosis, viral hepatitis, cytomegalovirus infection, other viral infections, pertussis, toxoplasmosis, brucellosis, tuberculosis (TB), syphilis, lymphocytic leukemias, and lead, carbon disulfide, tetrachloroethane, and arsenic poisonings. Drugs increasing the lymphocyte count include aminosalicyclic acid, griseofulvin, haloperidol, levodopa, niacinamide, phenytoin, and mephenytoin. Lymphopenia is a characteristic indication of AIDS. It is also seen in acute infections, Hodgkin's Disease, systemic lupus, renal failure, carcinomatosis, and with administration of corticosteroids, lithium, mechlorethamine, methysergide, niacin, and ionizing irradiation. Of all hematopoietic cells lymphocytes are the most sensitive to whole-body irradiation, and their count is the first to fall in radiation sickness.

Eosinophils - Eosinophilia (an excess number of eosinophils) is seen in allergic disorders and invasive parasitoses. Other causes include pemphigus, dermatitis herpetiformis, scarlet fever, acute rheumatic fever, various myeloproliferative neoplasms, irradiation, polyarteritis nodosa, rheumatoid arthritis, sarcoidosis, tuberculosis, coccidioidomycosis, smoking, idiopathically as an inherited trait, and in the resolution phase of many acute infections. Eosinopenia (a lack of eosinophils) is seen in the early phase of acute insults, such as shock, major pyogenic infections, trauma, surgery, etc. Drugs producing eosinopenia include corticosteroids, epinephrine, methysergide, niacin, niacinamide, and procainamide.

Basophils - A significant excess of basophil cells is an important clue to the presence of myeloproliferative disease as opposed to a leukemoid reaction. Other causes of basophilia include allergic reactions, chickenpox, ulcerative colitis, myxedema, chronic hemolytic anemias, Hodgkin's Disease, and status post-splenectomy. Estrogens, antithyroid drugs, and desipramine may also increase basophils.

Platelets. Platelets are cells in the blood that are necessary to help form a blood clot. A normal platelet count is between 150 to 350 thousand per cubic millimeter. Low platelet counts are called thrombocytopenia which can be caused by some drugs.

Blood cell counts table

Note; only the basic ranges are listed here. Normal ranges will be slightly different in different laboratories as there is no calibration of the tests between different labs.

Cell type and life stage group	Reference value range
Blood Volume	8.5 - 9.1% of total body weight
Bleeding time from surgical cut	Minutes
Over 16 years	2 - 9.5
Leuckocytes (white blood cells)	Thousands of cells per microliter
To 8 days	9.0 - 18.4
To 12 months	7.3 - 16.6
1-2 years	3.6 - 17.0
3-5 years	4.9 - 12.9
6-7 years	4.4 - 10.6
8-16 years	3.9 - 9.9
Over 16 years	4.0 - 9.4
Erythrocytes (red blood cells)	Millions of cells per microliter
To 8 days	4.0 - 6.8
To 2 months	3.2 - 6.1
3-12 months	2.8 - 5.2
1-3 years	3.6 - 5.3
4-16 years	3.7 - 5.8
Over 16 years	4.2 - 5.4
Erythrocyte sedimentation rate	Millimeters per hour
Female	1 –25
Male	0 –17
Hemoglobin	Grams per deciliter
To 2 months	9.0 - 16.6
3-12 months	9.2 - 13.1
1-3 years	10.7 - 13.1
4-11 years	11.1 - 14.7
12-16 years	12.8 - 16.8
Over 16 years	12.0 - 16.0
Hematocrit	Percentage
2-6 days	50 - 70
To 2 months	30 - 62
3-12 months	30 - 44
1-3 years	35 - 43
4-16 years	31 - 45
Over 16 years	36 - 46
MCV (Mean Corpuscular Volume)	Femtoliters
2-6 days	94 - 135
3-12 months	81 - 128
1-3 years	73 - 102
4-16 years	69 - 93
Over 16 years	78 - 98
MCH (Mean Corpuscular Hemoglobin)	Picograms per cell
2-6 days	29 - 41
To 2 months	29 - 38
3-12 months	21 - 35
1-3 years	23 - 31
4-16 years	22 - 34
Over 16 years	26 - 32
MCHC (Mean Corpuscular Hemoglobin Concentration)	Percentage per cell
2-6 days	24 - 36
To 2 months	29 - 41
3-12 months	25 - 38
1-3 years	21 - 36
Over 4 years	32 - 36
Thrombocytes	Thousands of cells per microliter
To 5 years	217 - 533
6-10 years	181 - 521
11-16 years	154 - 452
Over 16 years	150 - 440
Neutrophils	Percentage
To 8 days	24 - 51
To 12 months	16 - 50
To 2 years	18 - 54
To 3 years	21 - 60
To 4 years	24 - 65
4-9 years	32 - 64
10-14 years	35 - 65
15-16 years	37 - 65
Over 17 years	30 - 70
Lymphocytes	Percentage
To 8 days	32 - 62
To 12 months	38 - 73
To 2 years	34 - 72
To 3 years	29 - 66
To 4 years	25 - 63
4-16 years	25 - 55
Over 17 years	25 - 40
Monocytes	Percentage
To 8 days	0.6 - 9.3
To 2 years	0.6 - 11.0
3-16 years	1.1 - 13.2
Over 17 years	2.0 - 13.0
Eosinophils	Percentage
To 8 days	1.5 - 8.2
To 12 months	0.5 - 5.6
1-3 years	0.6 - 9.5
4-10 years	1.2 - 14.4
11-12 years	0.9 - 13.9
13-16 years	0.7 - 10.3
Over 17 years	0.5 - 7.0
Basophils	Percentage
To 8 days	0.2 - 1.2
To 12 months	0.3 - 1.2
2-4 years	0.3 - 1.4
5-16 years	0.3 - 1.7
Over 17 years	0.3 - 4.0
Platelets	Thousands of cells per millimeter
Over 17 years	150 - 350
Platelet mean volume	Micrometers cubed
Over 17 years	6.4 - 11.0
Remaining miscallaneous cells	Percentage
All ages	0 - 3

Blood cell counts references

• Geaghan SM. Hematologic values and appearances in the healthy fetus, neonate, and child. Clin Lab Med. 1999 Mar;19(1):1-37
• Fischbach FT. A manual of laboratory and diagnostic tests. Lippincott, Philadelphia, ISBN: 039755186X. 1998
• Kratz A, Lewandrowski KB. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Normal reference laboratory values. N Engl J Med. 1998 Oct 8;339(15):1063-72.
• Hale WE, Stewart RB, Marks RG. Haematological and biochemical laboratory values in an ambulatory elderly population: an analysis of the effects of age, sex and drugs. Age Ageing. 1983 Nov;12(4):275-84.