Brief Idea of Medical Test and its Interpretation
Author: Sumit Kumar Dubey


The CBC (Complete Blood Count) test examines red blood cells (RBCs), white blood cells (WBCs), and platelets.

WBCs count    Range: 4,300-10,800 cmm
WBCs (or leukocytes) help fight infections, so high WBCs indicates the infections inside body and may also indicate leukemia (increased number of WBCs). While low WBCs could be found by certain medications or health disorders such as viral infections temporarily interrupt the bone marrow to produce WBCs, cancer damages bone marrow and autoimmune disorders destroy WBCs as well as some medications (e.g. antibiotics) also destroy WBCs.

WBCs differential count

Neutrophils 40% to 60% of the total
Lymphocytes 20% to 40%
Monocytes 2% to 8%
Eosinophils 1% to 4%
Basophils 0.5% to 1%
The WBC differential count examines the numbers of different WBCs cells to check out the proper proportion to each other and if any irregularity found, may indicate an infection, inflammation, autoimmune disorders, anemia, or other health concerns.

RBCs erythrocyte count    Range: 4.2-5.9 million cmm
RBCs (red blood cells) count is an important because the number of red blood cells (RBCs) directly linked to weather cells or tissues receive oxygen properly or not. Fatigue is the common symptom of low RBC count. Certain dietary habits and medications can affect RBC count. This test is not indicate the problems actually, but if there are any irregularities other related tests will be necessary.

Hematocrit     Range: 45-52 % for men; 37-48% for women Hematocrit (HCT or Ht) test shows the ratio of the volume of red blood cells to the total volume of blood. Low HCT refers to anemia while high HCT to polycythemia.

Hemoglobin     Range: 13-18 g/dL for men; 12-16 g/dL for women
Hemoglobin (Hgb) delivers oxygen from the lungs to the entire body and then it returns to the lungs with carbon dioxide which we exhale. Low levels of hemoglobin indicate anemia.

Bilirubin     Range: 0.1-1.9 mg/dL

Bilirubin is a yellow pigment that found in blood and stool. Bilirubin is the product of dead red blood cells mediated by billiverdin in vertebrates and then travels to into the bile duct and finally stored in your gallbladder. Further, the bilirubin (as bile) is released into the small intestine that helps to digest fats and ultimately excreted with stool. When our body has high bilirubin concentration, the skin and the Sclera (whites of eyes) will start to yellow. This condition is called jaundice. This provides idea about the problem in liver and kidney functions, problems in bile ducts, and sometime anemia.

Mean corpuscular volume (MCV)    Range: 80-100 femtoliters
Mean corpuscular hemoglobin (MCH)    Range: 27-32 picograms
This test measures the average amount of hemoglobin in the typical red blood cell. Results that are too high could signal anemia, while those too low may indicate a nutritional deficiency.

Mean corpuscular hemoglobin concentration (MCHC)    Range: 28-36%
The MCHC test reports the average concentration of hemoglobin in a specific amount of red blood cells. Here again, we are looking for indications of anemia if the count is low, or possible nutritional deficiencies if it’s high.

Platelet count    Range: 150,000-400,000 mL
Platelets (or thrombocytes or blood clot cell) are a component of blood that actively involved in blood clotting along with the coagulation factors to stop bleeding via clotting blood vessel injury sites.

Mean Platelet Volume (MPV)    Range: 7.5-11.5 femtoliters
Higher MPV has associated with a risk of heart attack or stroke while lower MPV with risk of bleeding disorder.

ALT    Range: 8-37 IU/L

AST     Range:10-34 IU/L
These test is done to examine levels of the liver enzyme ALT (alanine aminotransferase), formerly called serum glutamic pyruvic transaminase (SGPT) and AST (Aspartate aminotransferase), formerly called serum glutamic oxaloacetate transaminiase (SGOT). ALT and AST are reasonably sensitive indicators of liver damage or injury from different types of diseases or conditions. They released into blood when the liver or heart is damaged. Healthy range in this test indicates good liver function. The higher range may indicate liver damage.

Albumin     Range: 3.9-5.0 g/dL
Albumin is a protein produced by the liver and preventing blood leakage from blood vessels. It also helps to carry some medicines via blood and facilitate tissue growth and healing. Moreover helps in osmotic pressure regulation. Albumin levels can be an indicator of liver or kidney problems. Globulin also present in the blood and certain globulins bind with haemoglobin while other globulins transport metals (such as iron) in the blood and prevent the infection. It also act as a carrier of some hormones, lipids and antibodies.

A/G ratio or total protein test Ratio: <1
Albumin and globulin both are present in the blood. The A/G ratio (albumin/globulin ratio) test compares levels of these proteins with one another. Elevated protein levels could indicate a health condition in need of attention.

A lower ratio of the total protein level indicates liver and kidney disorder or also can suggest whether protein is not digested or absorbed properly. Later, it could be predicted that there may be mal-nutrition or mal-absorption due to bowel disease (intestinal disorders) resulted prolonged inflammation of the digestive tract. A low A/G ratio may indicates over-production of globulins, as seen in multiple myeloma or autoimmune diseases in one hand or another hand under-production of albumin, as seen in cirrhosis or it may seen in case of kidney disease (nephrotic syndrome).

A higher ratio of total protein level associated with chronic inflammation or viral infections (such as hepatitis or HIV) and also a chance of bone marrow disorders such as multiple myeloma. A high A/G ratio indicates under-production of globulins (especially immunoglobulins), as seen in some leukemias (cancer of the blood cells).

BUN    Range: 10-20 mg/dL
BUN (blood urea nitrogen) is another test to measure of the kidney and liver functions. High values may occur in blood if there is a problem with kidney function. Heart failure, dehydration, or high protein diet can also increase the BUN level. BUN test calculate the amount of nitrogen in blood which comes from the nitrogenous metabolic waste like ammonia and urea. Both ammonia and urea is the protein metabolic waste of human body and excrete out of body via urine. Liver disease or damage can lower BUN level because ammonia to urea conversion takes place inside liver.

BUN/Creatinine ratio Ratio: 10:1-20:1
BUN/Creatinine ratio shows whether kidneys are eliminating waste properly or not. The substance creatine (Phospho-creatine) is synthesized in the liver and then transported to the muscle cells via bloodstream. Daily, 1 to 2% of muscle creatine is breakdown into creatinine which is taken out of blood by the kidneys and then passed out of your body in urine. Men tend to have higher levels of creatinine than women because, in general, they have a greater mass of skeletal muscle. If kidneys are damaged and not working properly, the amount of creatinine in urine decreased while its level in blood incresed.

Cockcroft-Gault Equation

Creatinine Clearance (mL/min) = 140 – age (years) × weight (kg) / 72 × serum creatinine concentration (mg/dL).

(For women, multiply result by 0.85)

Alkaline phosphatase     Range: 44-147 IU/L
Alkaline phosphatase (EC is a hydrolase enzyme responsible for removing phosphate groups from molecules (such as nucleotides, proteins, and alkaloids). Inside human body, alkaline phosphatase is present in all tissues throughout the entire body, but predominantly occurs in the liver, kidney, bone, intestinal mucosa. Moreover, serum consisted of only two types of alkaline phosphatase (a) skeletal and (b) liver, so high above the level indicate the liver or bone-related disease.

Lactate Dehydrogenase (LDH)    Range 140-280 U/L or 2.34-4.68 mkat/L

Lactate dehydrogenase (LDH or LD) is found mostly in the heart, muscles, liver, kidney, brain, and red blood cells and catalyzes the reversible conversion of lactate to pyruvic acid. Pyruvic acid (CH3COCOOH) is alpha-keto acids consisted of carboxylic acid and a ketone functional group. Inside cells, the pyruvic acid made up from glucose via glycolysis and converted back to glucose via gluconeogenesis or to fatty acids through a reaction with acetyl-CoA. It can also be used to construct the amino acid alanine and can be converted into ethanol or lactic acid via fermentation. Pyruvate (CH3COCOO-) is a key intermediate in several metabolic pathways. Pyruvic acid supplies energy to cells through the Krebs cycle (aerobic respiration) and alternatively ferments to produce lactate (anaerobic fermentation).

Thyroid is often recommended to patients if they have symptom like fatigue, weight gain, weight loss, nervousness, hyperactivity and so on. Test results below the normal range indicate hypothyroidism (low level of thyroid) while above the normal range associated with hyperthyroidism (highly active thyroid).

Test Normal Range
Thyroid-stimulating hormone (TSH) 0.3 to 3
Total T4 (total thyroxine) 4.5 to 12.5
Free T4 (free thyroxine) 0.7 to 2.0
Total T3 (total triiodothyronine) 80 to 220
Free T3 (free triiodothyronine) 2.3 to 4.2
Vitamin D Normal range: 30-74 ng/mL
Vitamin D is a fat-soluble secosteroids (a molecule similar to a steroid but with a broken ring) responsible for increasing absorption of calcium, iron, magnesium, phosphate, and zinc inside intestine. Vitamin D3 (chole-calciferol) and vitamin D2 (ergo-calciferol) are important in humans and can be ingested from the diet (or supplements), however very few foods contain vitamin D. The synthesis of cholecalciferol in the skin (dermal) is the major natural source of the vitamin and dependent on sun exposure (UV-B radiation). It is biologically inactive and requires enzymatic conversion (hydroxylation) in the liver and kidney in order to activate. Deficiency of vitamin D results broken bones and heart disease. Dermal cells can make vitamin D only when bare and free of sun blocking lotions is exposed to sunlight. 25-hydroxyvitamin D test helps to determine the need of supplements or vitamin D deficiency.

Uric Acid    Range- 2.4-6.0 mg/dL (female) and 3.4-7.0 mg/dL (male) Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen. It produced by breaks down of purines. Food and liquor such as dried beans, beer and wine contains high amount of purines and it also be created via natural process of cell breakdown inside human body. Mostly uric acid is dissolved in the blood, filtered through the kidneys and finally expelled outside of body via urination. Sometimes, the body produces higher fraction of uric acid or kidney does not able to filter out it, the hyperuricemia occurs and it associated with gout. Gout is a form of arthritis that mostly causes swelling of the joints in the feet. On other hand Hypouricemia (too little uric acid in blood) is a symptom of liver or kidney damage. Fanconi syndrome is a kidney disorder which prevents the absorption of glucose and uric acid.

Fasting glucose (blood sugar)     Range: 70-99 mg/dL
A fasting blood sugar level normally less than 100 mg/dL (5.6 mmol/L) but fasting blood sugar level from 100 to 125 mg/dL (5.6 to 6.9 mmol/L) is considered as pre-diabetes. The fasting blood glucose test is often used to diagnose diabetes. This test is usually done after at least eight hours of without food or liquid (except water).

Calcium     Range: 9.0-10.5 mg/dL
Human body regulates the calcium level in blood through the parathyroid hormone (PTH), and another hormone called calcitonin. Under normal routine body function, PTH increases when the calcium level in blood falls and decreases when calcium level rises. Calcitonin secretes when calcium level gets too high. When a person has hypercalcemia, his body unable regulate your calcium level as do normally. High level of calcium in the bloodstream indicates kidney problems, thyroid or parathyroid glands issues, lymphoma, problems in pancreas, or vitamin D deficiency.

Chloride    Range: 98-106 mEq/L
A high-salt diet and certain medications are often responsible for elevations in chloride ion and excess chloride may cause an acidic environment in the body. It could result dehydration, kidney disorders or adrenal gland dysfunction.

Phosphorus     Range: 2.4-4.1 mg/dL
Phosphorus along with calcium plays an important role in bone and teeth health. Too much phosphorus could associate with kidneys problem or also parathyroid gland. Alcohol abuse, long-term antacid use, excessive intake of diuretics or vitamin D as well as malnutrition can elevate phosphorus levels inside body.

Potassium    Range: 3.7-5.2 mEq/L
Potassium is an essential element for nerve impulses, muscle functions and heartbeats regulation. Diuretic drugs can cause low levels of potassium.

Sodium    Range: 135-145 mEq/L
Sodium is the member of the electrolyte family and helps to balance water levels inside body cells as well as helps with nerve impulses and muscle contractions. Irregular sodium levels may results dehydration, adrenal glands disorders, corticosteroids and liver or kidneys problems.

Total iron    Range- 60 to 170 mcg/dL

Iron is necessary for the formation of some proteins, hemoglobin, myoglobulin, and cytochrome. Also, it is necessary for oxygen transport, cellular respiration, and peroxide deactivation.

Carbon Dioxide (CO2)    Range- 23-29 mEq/L

CO2 level is associated with buffering system and a good indicator of acidity and alkalinity. As CO2 levels in the blood are affected by kidney and lung function so its normal range is a indicator of well kidney and lung function.

Lipid Profile (Panel)

The lipid profile tests measuring different types of cholesterol and triglycerides (fats) in bloodstream.

Total cholesterol

Healthy Below 200 mg/dL (below 5.18 mmol/L)
Borderline high 200 to 239 mg/dL (5.2 to 6.2 mmol/L)
High Above 240 mg/dL (above 6.2 mmol/L)
Triglycerides    Range: 40-160 mg/dL
Triglycerides are found in the bloodstream and may contribute to heart disease and other health problems.


Best Above 60 mg/dL
Good 50 to 60 mg/dL
Poor Below 40 mg/dL for men; below 50 mg/dL for women

Optimal Below 100 mg/dL
Near optimal 100 to 129 mg/dL
Borderline high 130 to 159 mg/dL
High 160 to 189 mg/dL
Very high Above 189 mg/dL
This test measures combined levels of both LDL (low density lipoprotein) and HDL (high density lipoprotein) LDL cholesterol is often referred to as "bad cholesterol" while HDL as relatively “good cholesterol”. Cholesterol is fat like substance made by liver of obtained as food source (packages as lipoproteins). Body needs cholesterol to make hormones, vitamin D and bile. LDL travels to blood stream and take up by endothelial cells when needed but in case of excess LDL in body it’s deposited inside the artery wall called plaque and affect smooth blood flow. Common affect area is coronary artery that feed heart (can causes heart attack) and carotid artery (can cause stroke). HDL protects against heart disease. Low scores are risk factors for heart disease.

Total cholesterol/HDL ratio (as per American Heart Association guidelines)

Optimal Ratio of 3.5 to 1
Healthy Ratio of 5 to 1 or lower
It is just another way of checking risk of heart disease as per guideline.

Abbreviations used for general medical test results

Measurement Units
cmm Cells per cubic millimeter
g/dL Grams per deciliter
IU/L International units per liter
mkat/L Katal per liter (catalytic activity)
mEq/L Milliequivalent per liter
mg/dL Milligrams per deciliter
mL Millilitre
mcg (µg)/dL Micrograms per deciliter
ng/mL Nanograms per milliliter
pg/mL Picograms per milliliter
fL femtoliter
mmol/L Millimoles per liter
Kindly note- Few data (such as normal ranges of test results) are borrowed from the internet with due thanks to the owner of authors.

About Author / Additional Info:
Research Scholar at
Department of Microbiology,
Science College, Bilaspur 495001