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Hematological Tests

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Hemoglobin Determination
It is performed generally by two methods the Sahli method or the cyanmethemoglobin method:

Normal Values Hb, g/dl
Men 14 – 18
Women 11.5 – 16.5
Children (up to 1 year) 11.0 – 13.0
Children (10 – 12 years) 11.5 – 14.5
Infants (full term cord blood) 3.5 – 19.5
  • Decrease in hemoglobin below the normal range indicates anemia.
  • It also drops in pregnancy due to hemodilution.
  • An increase is also seen in congenital heart disease due to reduced oxygen supply.
  • An increase in hemoglobin in emphysema.
  • An increase in hemoglobin in polycythemia.
Total Erythrocyte (Red Blood Cells) Count
Normal values:
    Normal Erythrocyte Normal Erythrocyte
  • Male – 4.5 to 6.0 x 106 cells/cu mm (ml)
  • Female – 4.0 to 4.5 x 106 cells/cu mm (ml)
  • At birth – 6.5 to7.25 x 106 cells/cu mm (ml)
  • A decrease in RBC count as also observed in old age, in pregnancy and in diseases which cause anemia.
  • An increase in the RBC count is observed in burns and cholera due to fluid loss.
  • An increase in the RBC count is also observed in chronic heart disease, emphysema and polycythemia.
  • Sometimes, false low counts can be due to edema, an error in calculation or due to improper dilution by the technician.
  • Sometimes, false high counts can be due to hemoconcentration, an error in calculation or due to an improper technique used by the technician.
Total Leucocyte (White Blood Cells) Count
Normal values:

Adults 4,000 – 10,000/cu mm (ml).
At birth 10,000 – 25,000/cu mm (ml).
1 to 3 years 6,000 – 18,000/cu mm (ml).
4 to 7 years 6,000 – 15,000/cu mm (ml).
8 to 12 years 4,500 – 13,500/cu mm (ml).
If there is an increase in the total WBC count and it is more than 10,000/cu mm (ml), it is known as leucocytosis.

Causes of Leucocytosis
Pathological
  • It occurs due to bacterial, viral, protozoal (malaria) or parasitic (filaria, hook worm) infections.
  • It is also observed in severe hemorrhage and in leukemia.
Physiological
    Abnormal leucocyte Abnormal leucocyte
  • At birth, the count is high and about 18,000/cu mm (ml), It gradually drops.
  • In full–term pregnancy, it goes to 12,000 to 15,000/cu mm (ml). It rises soon after delivery, and then returns to normal gradually.
  • Due to high temperature.
  • Due to severe pain.
  • Due to muscular exercise.
If there is a decrease in WBC count and it falls to less than 4,000/cu mm (ml), it is known as leucopenia.

Causes of Leucopenia
  • Bacterial infections like typhoid, paratyphoid, tuberculosis etc. reduces the count.
  • Viral infections like hepatitis, influenza, and measles also reduce the count.
  • Protozoal infections like malaria reduce the count.
  • Leukemia does it too.
  • Primary bone marrow depression (aplastic anemia).
  • Secondary bone marrow depression (due to drugs, radiation etc.).
  • Anemia (iron deficiency, megaloblastic etc.)
Differential WBC Count
There are five different kinds of WBCs

Monocyte Bosophil
Monocyte Bosophil

Normal Values (Male or Female)
Neutrophils 40 – 75%
Eosinophils 1 – 4%
Basophils 0 – 1%
Lymphocytes 20 – 45%
Monocytes 2 – 8%

Significance of the WBC Count
    Neutrophil Neutrophil
  • When there is an increase in eosinophils it is known as eosinophilia. It is observed in chronic inflammatory conditions, asthma, parasitic infestations, and in hypersensitivity reactions.
  • When there is a decrease in lymphocytes, it is known as lymphopenia. It is observed in acute stages of infections and where there is an excessive irradiation.
  • When there is an increase in neutrophils, it is known as neutrophilia. The common cause is pyogenic (pus forming) bacterial infections. When there is a decrease in neutrophils it is known as neutropenia. It is observed in bacterial infections such as typhoid, viral infection such as measles, influenza etc. It is also found in anemias (aplastic, megaloblastic, iron deficiency) and in suppression of bone marrow by various drugs and radiation.
  • When there is an increase in lymphocytes it is known as lymphocytosis. Lymphocytosis can be of two types, relative or absolute.
    • Relative Lymphocytosis: In this, the actual no of lymphocytes has not changed, but due to a decrease in neutrophils, the differential count shows an increase in lymphocytes.
    • Absolute Lymphocytosis:
      It is seen in:
      • Children.
      • Also seen when there are infections such as tuberculosis, typhoid, mumps, measles, cough, influenza syphilis and other chronic infections.
      • Infectious mononucleosis.
      • Chronic lymphatic leukemia.
  • When there is an increase in the number of monocytes, it is known as monocytosis. It is observed in tuberculosis, malaria, sub–acute bacterial endocarditis, typhoid and in Kala Azar.
  • A differential count is useful in identifying changes in the distribution of WBCs, which may be related to specific types of disorders. It also helps to know the severity of the disease and the degree of the response of the body.
Platelets Count
Platelets are very small in diameter – around 3 mm. They help in clotting of blood.

Normal platelet count is 250,000 to 500,000/cu mm (ml) and it is said to be adequate. If it is less than that, it is said to be inadequate.
Abnormalities of Erythrocytes (RBC)
In various types of anemia and in other diseases such as thalassemia, malaria, kidney failure etc., the mature RBCs show significant changes. Various changed RBCs seen are termed as microcytes, macrocytes, hypochromic, spherocytes, target cells, stomatocytes, anisocytosis, poilkilocytosis, sickle cells, ovalocytes, elliptocytes, acanthocytes, burr cells, siderocytes, basophilic stippling, howell–jolly body, cobot ring, schi stocytes, crescent bodies and creneted cells depending upon their morphology.
Abnormalities of Leucocytes (WBC)
Hyper segmented Neutrophil Hyper segmented Neutrophil
Most abnormalities are seen in Neutrophils.
Different WBCs having abnormalities are termed as myelocytes, promyelocytes, blasts, metamyelocytes, plasma cell, smudge cells etc.



Parasites
Blood parasites cause a number of ailments which are more prevalent in tropical counties. The common diseases caused are malaria, kala azar and sleeping sickness.
Plasmodium Falciparum (Click on image to large view) Plasmodium Falciparum
The parasites found are:
A) The following parasites cause malaria
  • Plasmodium vivax.
  • Plasmodium malariae.
  • Plasmodium falciparum.
  • Plasmodium ovale.
B) The following parasites cause visceral leishmaniasis, dumdum fever or kala azar
  • Leishmania donovani.
C) The following parasites cause African sleeping sickness
  • Trypanosoma brucei gambiense.
D) The following parasites cause filaria
    Mansonella ozzardi Wuchereria bancrofti Lao loa
    Mansonella ozzardi Wuchereria bancrofti Lao loa

  • Wuchereria bancrofti.
  • Mansonella perstans.
  • Brugia timori.
  • Mansonella ozzardi.
  • Brugia malayi.
  • Lao loa.
Packed Cell Volume (PCV)
PCV (packed cell volume) is the amount of packed red blood cells after centrifugation. It is expressed in the percentage of total blood volume.
Normal values
Male: 42–52%.
Female: 36–48%.
Late pregnancy: 23–37%.
Increase in PCV is due to polycythemia, dehydration, emphysema, and congenital heart disease.
Decrease in PCV is due to different types of anemia, hydremia (excessive fluid in the blood which occurs in pregnancy).
Mean Corpuscular Volume (MCV)
MCV – Mean Cell Volume
  • Normal value: 82–92 cu mm.
  • Increased MCV indicates macrocytic anemias.
  • Decreased MCV indicates microcytic anemias.
Mean Corpuscular Hemoglobin (MCH)
MCH – Mean Cell hemoglobin
  • Normal value: 27–32 pg (pg = 1 picogram = 10–12 g).
  • Increased value indicates macrocytic anemia.
  • Decreased value indicates hypochromia.
Mean Corpuscular Hemoglobin Concentration (MCHC)
Normal Value: 32–36%.
  • Increased value indicates spherocytosis.
  • Decreased value indicates hypochromic anemias.
Color Index
It is average amount of hemoglobin in the red cell compared to normal.
  • Normal color index: 0.85–1.15.
  • Increase in the color index indicates megaloblastic anemias.
  • Decrease in the color index indicates hypochromic anemia.
Tabular Representation of Normal Values
Blood Routine – Normal Values

Test Normal Values
Hemoglobin Men 13.5–17.5%
Women 11.5–16.5%
Total WBC Count Adults: 4000–11000/cu.mm
Differential Count Neutrophils 40–75%
Eosinophils 1–6%
Lymphocytes 20–45%
Monocytes 2–10%
Basophils 0–1%
ESR: (Westegren): 1 hr Men 1–10 mm
  Women 5–15 mm
Platelet Count 1.5–4.0 lakhs/cu.mm
Reticulocyte Count Adults: 0.2–2%
RBC (Erythrocyte) Count Men 4.5–6.5 million/cu.mm
Women 3.8–5.8 million/cu.mm
Mean Corpuscular Volume 75–97 fl
Mean Corpuscular Hemoglobin 26–33 pg
Mean Corpuscular Hemoglobin Concentration 32–35%
Haematocrit (PCV) Men 40–54%
Women 37–47%
Glossary of Terms Used
Emphysema
It means stretching of body tissue due to the accumulation of gas or air in the tissue or organ. Pulmonary emphysema is a chronic lung disease in which air sacs of the lungs are stretched until the elastic fibers in them are destroyed.
Polycythemia
It is an excess of red blood cells. It may be temporary due to lack of oxygen in the blood. It may be due to heart disease or continued exposure to high altitudes. Also, if may be due to disorder of the bone marrow.
Myeloid leukemia
It is a kind of blood cancer.
Congenital heart disease
It means any heart disorder that is present at birth. Most common is a hole between two ventricles, either narrowing or the wrong position of the aorta (the main artery), or constriction of valves on the left side of the heart with weakness of the heart muscle.
Aplastic anemia
It is a disease of the bone marrow. It produces deficiency of the red blood cells, white blood cells as well as platelets.
Infectious mononucleosis Infectious mononucleosis
Infectious mononucleosis
Also called glandular fever caused by a herpes virus (Ebstein–Barr virus).
Megaloblastic anemia
It is a disease of the bone marrow. Here, immature abnormal red blood cells are found in the blood.
Edema
Swelling of any part of the body due to retention of fluids.
Sub–acute bacterial endocarditis
Endocarditis means inflammation of the endocardium, the inner lining of the heart. When bacteria infects it, then it is called bacterial endocarditis. All types of endocarditis, if untreated are fatal.
Microcytic anemia
A decrease in red blood cells, reduced hemoglobin, PCV, MCV, MCH and MCHC.
Macrocytic anemia
A decrease in red blood cells, reduced, hemoglobin, elevated MCH and MCV with normal MCHC.
Introduction
Blood Donation Blood Donation
Blood is connective tissue. It circulates in closed blood vessels in the system. The circulating blood consists of erythrocytes (red blood cells), leucocytes (white blood cells), and platelets or thrombocytes in a pale yellow colored fluid called plasma.

When blood is given to a pathological lab for routine check up of blood CBC – a complete blood count is performed.


Comments (3)Add Comment
0
Yoseph
May 21, 2010
213.55.95.193
Votes: +0
Mr

i am a alboratory tecnology student may get information on preanalytical , analytical and post analytical errors and remedies for prothrombin time and partial thromboplastin time tests

0
Tewodros Duguma
September 08, 2010
213.55.70.5
Votes: +1
Medical Laboratory Technology student

I am a Medical Lboratory tecnology student. may i get information on preanalytical , analytical and post analytical errors and remedies reticulocyte count?

0
Gyabaa Sampson
January 29, 2011
80.87.92.49
Votes: -1
...

I am a Medical Lboratory tecnology student. may i get information on preanalytical , analytical and post analytical errors and remedies for culture and sensitivity test?

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