How to read your blood report — a doctor's guide for non-doctors.

If you have ever stared at a blood report dotted with red asterisks and felt a small panic, you are not alone. Reports today list dozens of values, each flagged against a "normal range" that varies by lab, age, sex and even the time of day. Here is a section-by-section walk-through of what each test actually means.

The CBC — your full blood count

The Complete Blood Count is the most commonly ordered test. It looks at three families of cells in your blood:

Haemoglobin and red cells

Value	Normal range	What it means
Haemoglobin (Hb)	Men 13–17, Women 12–15 g/dL	Oxygen-carrying capacity. Low = anaemia. Below 10 needs investigation.
MCV (mean cell volume)	80–100 fL	Cell size. Low (microcytic) suggests iron deficiency; high (macrocytic) suggests B12/folate deficiency.
RDW	11.5–14.5%	Cell size variability. Often raised early in iron deficiency before Hb drops.

White cells (WBC)

Normal total WBC: 4,000–11,000/µL. Mild elevation often just means recent infection or stress. Markedly raised (above 15,000) or low (below 3,000) needs attention. The differential — neutrophils, lymphocytes, monocytes, eosinophils, basophils — gives clues about the type of infection or allergy.

Platelets

Normal: 1.5–4 lakh/µL (150,000–400,000). Slight variation is common. Below 1 lakh needs review; below 50,000 is urgent. Above 4.5 lakh may signal inflammation.

Fasting glucose and HbA1c

Value	Normal	Pre-diabetes	Diabetes
Fasting glucose	< 100 mg/dL	100–125 mg/dL	≥ 126 mg/dL (on two occasions)
HbA1c	< 5.7%	5.7–6.4%	≥ 6.5%
Random / post-meal	< 140 mg/dL	140–199	≥ 200 mg/dL

If you are pre-diabetic, you have a 5–10% per year chance of progressing to diabetes — but also the best window to reverse it through diet, weight loss and exercise. More on diabetes monitoring →

Lipid profile — cholesterol

Value	Healthy adult target
Total cholesterol	< 200 mg/dL
LDL ("bad") cholesterol	< 100 mg/dL (lower if you have diabetes or heart disease)
HDL ("good") cholesterol	> 40 mg/dL men, > 50 mg/dL women
Triglycerides	< 150 mg/dL
Non-HDL cholesterol	< 130 mg/dL

Kidney function (KFT / RFT)

Value	Normal range
Creatinine	Men 0.7–1.3 mg/dL · Women 0.6–1.1 mg/dL
Blood urea	15–40 mg/dL
eGFR (estimated glomerular filtration rate)	> 90 mL/min/1.73m² is ideal; 60–89 mildly reduced; below 60 needs evaluation
Uric acid	Men < 7, Women < 6 mg/dL

Single mildly raised creatinine doesn't always mean kidney disease — dehydration, gym workouts, high-protein meals, and certain medications (metformin, NSAIDs) can push it up briefly. Trends over time matter most.

Liver function (LFT)

Value	Normal range	What it means
SGPT (ALT)	< 40 U/L (often lower today)	Liver cell health. Mildly raised: very common, often fatty liver.
SGOT (AST)	< 40 U/L	Less liver-specific than ALT. Raised in liver and muscle injury.
Alkaline phosphatase (ALP)	40–130 U/L	Bile flow and bone turnover. Raised in bile duct issues, bone disorders.
GGT	< 60 U/L	Sensitive to alcohol and bile duct problems.
Total bilirubin	0.2–1.2 mg/dL	Mildly raised in Gilbert's syndrome (harmless), or liver/gallbladder issues.
Total protein / albumin	6.6–8.3 / 3.5–5.2 g/dL	Lower in chronic disease, malnutrition.

Thyroid function (TSH most important)

• TSH (thyroid stimulating hormone): 0.4–4.0 mIU/L is the typical reference. Higher = underactive thyroid (hypothyroidism); lower = overactive (hyperthyroidism).
• Free T4 (FT4): 0.8–1.8 ng/dL. Ordered if TSH is abnormal.
• Free T3 (FT3): 2.3–4.2 pg/mL. Less useful in routine screening.

In pregnancy, the target TSH is lower (< 2.5 in first trimester). Mildly raised TSH (subclinical hypothyroidism) in non-pregnant adults often needs only watching, not treatment.

Vitamin D and B12 — the two everyone in India is low in

• Vitamin D (25-OH): above 30 ng/mL is sufficient; 20–30 insufficient; below 20 deficient. About 70% of Indian adults are insufficient or deficient.
• Vitamin B12: above 300 pg/mL is sufficient; 200–300 borderline; below 200 deficient. Vegetarians, diabetics on metformin, and adults above 60 are at highest risk.

Replacement is cheap and well-tolerated. Re-test 3 months after starting supplements.

Inflammatory markers — read with caution

• ESR: rises in many conditions, very non-specific. A mildly raised ESR in an otherwise well person usually doesn't need investigation.
• CRP: more specific for active inflammation. Useful for tracking infection severity or autoimmune disease activity.
• D-dimer: should only be ordered when there is a specific reason (suspected clot). Raised D-dimer on a routine panel often causes unnecessary panic.

How to talk to your doctor about the report

1. Bring the actual report (paper or PDF) — not a verbal summary.
2. Bring any previous reports for comparison. Trends matter.
3. Tell your doctor about any new symptoms, medications, supplements, recent illnesses or unusual meals before the test.
4. Ask specifically: which values matter for me, and which can I ignore?
5. Ask: what would the next test be, and when?