Friday, May 23, 2008

Deciphering Blood Test Results

For the whole of this week, Diya has been down with a strange fever. Spurts of high temperature touching 103F, stomach aches, intermittent shivering and sleepless nights. The pediatrician first suggested the usual combination of Calpol and Ibugesic, but when the fever carried on beyond a week, he told us to get the blood-tests done. Typhoid is what he suspected.

The results came in yesterday and, thankfully, typhoid has been ruled out. But the fever still lingers. While we keep our fingers crossed, hoping that this is another benign viral fever that dropped out of the crazy summer rains, I was wondering what all those blood-test acronyms actually meant...

Here is the alphabet soup, decoded and simplified:

Packed cell volume (PCV) or hematocrit (Ht or HCT) or erythrocyte volume fraction (EVF) is the proportion of blood volume that is occupied by red blood cells. It is normally about 46% for men and 38% for women.

Leukocyte Count. Leukocytes are commonly called white blood cells, which are the workhorses of the immune system. They defend the body from infection and foreign material. Low leukocyte counts indicate that your immune system is not functioning optimally and that you may be more susceptible to infection.

DLCDifferential Leukocyte Count. This test measures the composition of each type of White blood cells (leucocytes) that come in assorted shapes and sizes:
  1. Polymorphs ('Poly'=many, 'morphs'=shapes) aka Neutrophils ('neutro' = neutral, 'phil' = loving) because they are neither acidic nor alkaline. Normal range - 40% to 80%.
  2. Lymphocytes ('lympho' = lymph, 'cytes' = cells) are the cells that have the ability to recognise foreigners in the blood. A false alarm sent out by lymphocytes is called an allergic reaction. Normal range - 20% to 40%.
  3. Eosoinophils ('Eosin' = the name of a red dye, 'phil' = loving) contain poisonous chemicals (toxins) for destroying parasites. Cause a false alarm in Asthma and Eosinophilia. Normal range - 0 to 3% of whitle blood cells.Normal range - 1% to 6%.
  4. Monocytes ('mono' = single, 'cytes' = cells) These single-blob cells break up foreign particles and substances for the lymphocytes, which can then handle the recognition of the small fragments. Normal range - 2% to 10%.
  5. Basophils ('baso' = alkali, 'phil' = loving) release histamine when such an allergic reaction happens, resulting in the dialation (widening) of cappillaries.

Platelet Count

Blood platelets, ('little plates') are some of the tiniest components of blood, vital for clotting of the blood and protection from bleeding. Normal range - 0.15 tp 0.4 million/

ESR Westergren's
ESR stands for Erythrocyte Sedimentation Rate which measures the extent of inflamation in the body. Anaemia, TB and cancer are known to spike ESR readings. Normal range - 3 to 13 mm/hour for children and for adult males below 15mm/hr and women, below 20mm/hr.
Westergren's is method for estimating the sedimentation rate of red blood cells in whole blood by mixing venous blood with an aqueous solution of sodium citrate and allowing the mixture to stand in an upright standard pipet and, after one hour, reading the millimeters the cells have descended.

RBC Count
Number of Red Blood Copuscles (RBC) RBCs contain hemoglobin, which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work. Normal count - Male: 4.7 to 6.1 million cells per microliter (cells/mcL); Female: 4.2 to 5.4 million cells/mcL

Haemoglobin Count
Measures the amount of oxygen-carrying protien in blood.
The normal haemoglobin count is 12-16 grams of haemoglobin per deciliter of blood in females and 14-18 grams of haemoglobin per deciliter of blood in males

Mean corpuscular volume (MCV)
Measures the average size of your RBCs. The MCV is elevated when your RBCs are larger than normal (macrocytic), for example in anemia caused by vitamin B12 deficiency. When the MCV is decreased, your RBCs are smaller than normal (microcytic) as is seen in iron deficiency anemia or thalassemias.

Mean corpuscular hemoglobin (MCH)
Measures the average amount of oxygen-carrying hemoglobin inside a red blood cell.

Mean corpuscular hemoglobin concentration (MCHC)
A calculation of the average concentration of hemoglobin inside a red cell. Decreased MCHC values (hypochromia) are seen in conditions where the hemoglobin is abnormally diluted inside the red cells, such as in iron deficiency anemia and in thalassemia. Increased MCHC values (hyperchromia) are seen in conditions where the hemoglobin is abnormally concentrated inside the red cells, such as in burn patients and hereditary spherocytosis, a relatively rare congenital disorder.

Red cell distribution width (RDW)
A calculation of the variation in the size of your RBCs. In some anemias, such as pernicious anemia, the amount of variation (anisocytosis) in RBC size (along with variation in shape – poikilocytosis) causes an increase in the RDW.

Among the most sensitive and widely used liver enzymes are the aminotransferases. If the liver is injured, the enzymes spill out, raising the enzyme levels in the blood and signaling the liver damage. Two key enzyms are AST and ALT. The enzyme aspartate aminotransferase (AST) is also known as serum glutamic oxaloacetic transaminase (SGOT); and alanine aminotransferase (ALT) is also known as serum glutamic pyruvic transaminase (SGPT). Normal range - SGOT - 8 to 40 units/ litre; SGPT - 5-35 units/litre

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