Your doctor orders a blood test. A few days later, a report arrives — several pages of numbers, abbreviations, and columns labelled "normal range." You look at it, see that some numbers have an "H" (high) or "L" (low) flagged next to them, feel a mild wave of anxiety, and put the paper away.
This is the experience of most Indians who get blood tests. The information is there. The understanding is not.
This article changes that. It explains, in plain language, what every major blood test actually measures, what the numbers mean, what is genuinely worrying and what is not, and what to ask your doctor when you go back.
Important before we begin: This guide helps you understand your report, not diagnose yourself. Blood test results must always be interpreted in the context of your symptoms, medical history, other tests, and a doctor's examination. A number outside the "normal range" does not automatically mean something is wrong — context matters enormously.
Complete Blood Count (CBC) — The Starting Point
A CBC (Complete Blood Count, also called a haemogram) is the most common blood test. It analyses the cells in your blood and gives you a picture of your overall health.
Haemoglobin (Hb or Hgb)
What it measures: The protein in red blood cells that carries oxygen. Low haemoglobin = anaemia = not enough oxygen reaching your organs and tissues.
Normal ranges:
- Men: 13.5–17.5 g/dL
- Women: 12.0–15.5 g/dL
- Children (6–12 years): 11.5–15.5 g/dL
- Pregnant women: above 11.0 g/dL
What low Hb means (anaemia):
- Mild (10–12 in women, 10–13 in men): Fatigue, breathlessness on exertion, pale skin
- Moderate (8–10): More significant fatigue, palpitations
- Severe (below 8): Serious — needs immediate medical attention
The India context: Anaemia is extremely common, especially in women and children. Causes include iron deficiency (most common), B12 deficiency, folate deficiency, chronic disease, and blood loss. If your Hb is low, your doctor should identify the cause — not just treat the number.
What high Hb means: Can indicate dehydration, smoking, or (rarely) a blood disorder. Usually requires further investigation.
WBC — White Blood Cells (Total Leucocyte Count / TLC)
What it measures: Your immune system's fighting cells. The number tells you about infection and immune function.
Normal range: 4,000–11,000 cells per microlitre (or 4–11 × 10³/μL)
High WBC (above 11,000): Usually means your body is fighting something — an infection (bacterial infections typically raise WBC more than viral), inflammation, or in rare cases, leukaemia. A moderately elevated WBC during a fever is normal and expected.
Low WBC (below 4,000): Can indicate viral infections (like dengue, which typically suppresses WBC), certain medications, bone marrow issues, or severe immune deficiency.
Platelets (PLT)
What it measures: The tiny cells responsible for blood clotting when you have a cut or injury.
Normal range: 1.5 lakh–4.5 lakh per microlitre (150,000–450,000/μL)
Low platelets (thrombocytopenia): Can mean increased bleeding risk. In India, dengue fever is a major cause of sudden platelet drop — this is why dengue patients are hospitalised when platelets fall below 50,000. Other causes: viral infections, certain medications, liver disease.
High platelets: Usually reactive (after infection, surgery, or iron deficiency anaemia) and not concerning. Rarely indicates a bone marrow disorder.
Differential Count (DC)
This breaks down the WBC into types — neutrophils, lymphocytes, monocytes, eosinophils, basophils. Your doctor uses this to understand what type of infection or inflammation you have:
- High neutrophils → bacterial infection
- High lymphocytes → viral infection
- High eosinophils → allergy, parasitic infection
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Blood Sugar Tests — Understanding Diabetes Risk
Fasting Blood Glucose (FBS)
What it measures: Your blood sugar level after at least 8 hours without food. This is the baseline measure of how your body manages glucose.
Normal ranges:
- Normal: Below 100 mg/dL
- Pre-diabetes: 100–125 mg/dL
- Diabetes: 126 mg/dL or above (confirmed with a second test)
Fasting sugar of 110? You are in the pre-diabetes zone. This is a warning, not a diagnosis. With lifestyle changes — diet, exercise, weight management — many people return to normal.
Post-Prandial Blood Glucose (PPBS)
What it measures: Blood sugar 2 hours after eating a standard meal. Shows how well your body clears glucose after food.
Normal ranges:
- Normal: Below 140 mg/dL
- Pre-diabetes: 140–199 mg/dL
- Diabetes: 200 mg/dL or above
HbA1c (Glycosylated Haemoglobin)
What it measures: The most important diabetes test. Unlike fasting sugar (which shows today), HbA1c shows your average blood sugar over the past 3 months. This is because glucose sticks to haemoglobin in red blood cells, which live for about 3 months.
Normal ranges:
- Normal: Below 5.7%
- Pre-diabetes: 5.7%–6.4%
- Diabetes diagnosis: 6.5% or above
- Well-controlled diabetes (target for most diabetics): Below 7%
- Poorly controlled: 8% and above
Why HbA1c matters: It cannot be manipulated by eating well for a day before the test. It gives a true long-term picture. If you have diabetes, your doctor will monitor this every 3–6 months.
Practical example: HbA1c of 8.2% means your average blood sugar over 3 months was approximately 189 mg/dL — significantly above the target range. This is a signal that medication, diet, or activity needs adjustment.
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Thyroid Function Tests (TFT)
The thyroid gland regulates your metabolism, energy, mood, weight, and much more. Thyroid disease is extremely common in India — and largely underdiagnosed.
TSH (Thyroid Stimulating Hormone)
What it measures: TSH is produced by the brain (pituitary gland) to tell the thyroid to make more or less hormone. When the thyroid is underactive (hypothyroid), TSH goes high; when overactive (hyperthyroid), TSH goes low.
Normal range: 0.4–4.0 mIU/L (some labs use 0.5–5.0 — check your lab's reference range)
High TSH (hypothyroidism — underactive thyroid):
- Common symptoms: fatigue, weight gain, cold intolerance, constipation, depression, irregular periods in women, hair loss
- Treatment: Levothyroxine (thyroid hormone tablet) — inexpensive and available at Jan Aushadhi Kendras for ₹5–₹10 per strip
Low TSH (hyperthyroidism — overactive thyroid):
- Common symptoms: weight loss, palpitations, sweating, anxiety, tremors, diarrhoea
- Treatment: Anti-thyroid medication, radioactive iodine, or surgery depending on cause
T3 and T4
- T3 (Triiodothyronine) and T4 (Thyroxine) are the actual thyroid hormones
- Normal T4 (free): 0.8–1.8 ng/dL; Normal T3 (free): 2.3–4.2 pg/mL
- TSH is usually the first test. T3 and T4 are added if TSH is abnormal or if hyperthyroidism is suspected
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Lipid Profile — Understanding Cholesterol
This test measures the fats (lipids) in your blood and assesses your cardiovascular risk.
Total Cholesterol
Normal: Below 200 mg/dL. Above 240 is high risk.
LDL — "Bad" Cholesterol
LDL deposits in artery walls and causes blockages. Lower is better.
- Optimal (for most people): Below 100 mg/dL
- Near optimal: 100–129 mg/dL
- Borderline high: 130–159 mg/dL
- High: 160–189 mg/dL
- Very high risk: 190+ mg/dL
If you have diabetes or heart disease, your doctor may target LDL below 70 mg/dL.
HDL — "Good" Cholesterol
HDL removes excess cholesterol from arteries. Higher is better.
- Low (risk factor): Below 40 mg/dL in men, below 50 mg/dL in women
- Protective: Above 60 mg/dL
Ways to raise HDL: Regular aerobic exercise (30 min, 5 days a week), quitting smoking, moderate healthy fats (nuts, olive oil, mustard oil).
Triglycerides
What they measure: The fat stored from excess calories. High triglycerides with low HDL is a dangerous combination for heart disease.
- Normal: Below 150 mg/dL
- Borderline: 150–199 mg/dL
- High: 200–499 mg/dL
- Very high: 500+ mg/dL (pancreatitis risk)
Common causes of high triglycerides: Excessive refined carbohydrates (white rice, maida, sugar, sugary drinks), alcohol, uncontrolled diabetes, thyroid problems.
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Kidney Function Tests (KFT / RFT)
Creatinine
What it measures: A waste product filtered by the kidneys. When kidneys are damaged, creatinine rises.
- Normal (men): 0.7–1.2 mg/dL
- Normal (women): 0.5–1.0 mg/dL
High creatinine: Suggests reduced kidney function. The degree of elevation tells your doctor how much function remains.
eGFR (Estimated Glomerular Filtration Rate)
Often calculated from creatinine. Shows what percentage of kidney function remains:
- Above 90: Normal
- 60–89: Mild reduction
- 30–59: Moderate — requires regular monitoring
- 15–29: Severe — specialist care needed
- Below 15: Kidney failure — dialysis or transplant consideration
Blood Urea Nitrogen (BUN) / Blood Urea
Another waste product. High urea alongside high creatinine confirms kidney problem. Can also be high if you eat very high protein or are dehydrated.
Uric Acid
Normal: 3.5–7.0 mg/dL in men; 2.5–6.0 mg/dL in women
High uric acid (hyperuricemia): Can cause gout (severe joint pain, especially in big toe), kidney stones. Common causes: red meat, shellfish, alcohol, sugary drinks, and some medications. Many people with high uric acid have no symptoms until a gout attack.
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Liver Function Tests (LFT)
SGPT (ALT — Alanine Aminotransferase)
What it measures: An enzyme mainly found in liver cells. When liver cells are damaged, SGPT leaks into the blood.
- Normal: 7–56 units/litre (ranges vary by lab)
- Mildly elevated (1–3× normal): Can be from fatty liver (very common in India), viral infection, medication
- Highly elevated (10× or more): Hepatitis (viral, alcoholic), serious liver damage
SGOT (AST — Aspartate Aminotransferase)
Found in liver but also in heart muscle and other tissues. Elevated together with SGPT confirms liver involvement. If SGOT is high but SGPT is normal, a heart issue may be considered.
Total Bilirubin
What it measures: A breakdown product of red blood cells processed by the liver.
- Normal: 0.2–1.2 mg/dL
- High bilirubin causes jaundice (yellowing of skin and eyes)
- Causes: Liver disease, blocked bile duct, rapid red blood cell breakdown
Albumin
Produced by the liver. Low albumin in a liver test panel suggests chronic liver disease or malnutrition. Normal: 3.5–5.0 g/dL.
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How to Use This Guide When You Have Your Report
Step 1: Find each test in your report and compare the number to the normal range given by your lab (every lab's ranges are slightly different — always use the range on your specific report, not just the numbers here).
Step 2: Mark any values that are outside the range — either flagged H (high) or L (low).
Step 3: Note the degree — slightly outside range is very different from significantly outside range.
Step 4: Write specific questions for your doctor: "My HbA1c is 6.1% — you said that's pre-diabetic. What should I change in my diet?" is a much better question than "Is my report okay?"
Step 5: Do not make medication decisions based on a report alone. A blood test is one input; your doctor considers it alongside your symptoms, examination, and other factors.
Where to Get Affordable Blood Tests
Government sources (often free or subsidised):
- Primary Health Centres (PHC) — basic tests often free
- District hospitals — blood tests at government rates
- PM-JAY (Ayushman Bharat) card holders — many tests covered at empanelled hospitals
Private labs — compare prices:
- Thyrocare, SRL, Metropolis, Dr. Lal PathLabs — often have online booking with discounts
- A "full body checkup" package typically costs ₹500–₹1,500 and includes CBC, sugar, lipid, kidney, liver, and thyroid
- Fasting for 8–12 hours before the test is required for sugar and lipid tests
Sources
- Indian Council of Medical Research (ICMR) — Standard Treatment Guidelines
- Ministry of Health and Family Welfare — National Programme for Non-Communicable Diseases
- American Diabetes Association — Standards of Medical Care in Diabetes, 2025
- Indian Thyroid Society — Clinical Practice Guidelines
- Cardiological Society of India — Lipid Guidelines, 2024
- National Family Health Survey (NFHS-5), 2019–21
