Complete Blood Count (CBC)
The most common blood test ordered in India. It tells you about your red cells, white cells, and platelets — and can catch anaemia, infections, and more.
A CBC is a simple blood test that counts your red blood cells, white blood cells, and platelets. It's the single best screening test for anaemia — which affects roughly half of Indian women — and gives early clues about infections, inflammation, and blood disorders.
What is a CBC?
A Complete Blood Count is a blood test that measures the cells flowing through your bloodstream. It's probably the first test any doctor in India will order — and for good reason. It gives a snapshot of three things:
- Red blood cells (RBCs) — carry oxygen from your lungs to the rest of your body. Low RBCs or low haemoglobin = anaemia.
- White blood cells (WBCs) — your immune fighters. High counts can signal infection or inflammation; very low counts can mean immune suppression.
- Platelets — help your blood clot. Low platelets raise bleeding risk; high platelets may signal inflammation or other issues.
The report also includes RBC indices like MCV (the size of your red cells) and MCH (how much haemoglobin each cell carries). These help your doctor figure out why your haemoglobin might be low — whether it's iron deficiency, B12 deficiency, or something else.
What your number means
Here are the key values you should look at when you get your CBC report:
| Marker | Lab normal | Optimal |
|---|---|---|
| Haemoglobin | M: 13–17 · F: 12–15 g/dL | M: 14–16 · F: 13–15 g/dL |
| WBC | 4,000–11,000 /µL | 4,500–7,500 /µL |
| Platelets | 1.5–4.0 lakh /µL | 1.75–3.0 lakh /µL |
| MCV | 80–100 fL | 85–95 fL |
| RDW | <14.5% | <13% |
Low haemoglobin + low MCV = likely iron deficiency (extremely common in Indian women and vegetarians). Low haemoglobin + high MCV = likely B12 or folate deficiency. High RDW = your red cells are uneven in size, which often points to a nutritional deficiency even before haemoglobin drops.
How to improve your numbers
If your CBC shows a problem, the fix depends on what's off:
- Low haemoglobin (iron deficiency) — take iron bisglycinate (the form that doesn't upset your stomach), pair it with vitamin C for better absorption, and avoid tea/coffee within an hour of your iron-rich meal.
- Low haemoglobin (B12 deficiency) — common in vegetarians. Supplement with methylcobalamin (active B12). 1,000–2,000 mcg/day sublingual works well.
- High WBC (chronic) — rule out infection first. If persistent, it can signal chronic inflammation. Focus on anti-inflammatory basics: sleep, omega-3, reduce processed food.
- Low platelets — see your doctor. Could range from viral (dengue, common in India) to immune-related. Don't self-treat low platelets.
Track your CBC over time — not just once
eterni connects your reports across months so you can see if your haemoglobin is actually trending up after starting iron.
Get early accessFrequently Asked Questions
What does a CBC test check for?
A CBC measures the three main types of blood cells: red blood cells (which carry oxygen), white blood cells (which fight infection), and platelets (which help blood clot). It also reports haemoglobin, hematocrit, and RBC indices like MCV that help identify anaemia type.
Do I need to fast before a CBC?
No. A CBC does not require fasting. You can eat and drink normally before the test. However, if your doctor has ordered other tests alongside (like fasting glucose or a lipid panel), you may need to fast for those.
What is a normal haemoglobin level in India?
Lab reference ranges are typically 13–17 g/dL for men and 12–15 g/dL for women. Optimal levels for longevity and energy are 14–16 g/dL for men and 13–15 g/dL for women. Anaemia is very common in India — roughly 50% of Indian women have haemoglobin below 12 g/dL.
How often should I get a CBC done?
Once a year as part of a routine health check-up. More frequently (every 3–6 months) if you have a known condition like anaemia, are on medications that affect blood counts, or are tracking a supplement protocol that targets iron or B12.
What the components actually tell you
Beyond the headline haemoglobin number, a CBC packs a lot of diagnostic signal:
- MCV (Mean Corpuscular Volume) — tells you the size of your red cells. Low MCV (microcytic) points to iron deficiency or thalassemia trait — both very common in India. High MCV (macrocytic) points to B12 or folate deficiency.
- RDW (Red Cell Distribution Width) — measures how varied your red cell sizes are. Elevated RDW is increasingly recognised as an independent predictor of cardiovascular risk and all-cause mortality, even when haemoglobin looks normal.
- Neutrophil-to-Lymphocyte Ratio (NLR) — calculated from the WBC differential. An NLR above 3 is associated with systemic inflammation and worse outcomes in cardiovascular disease, infections, and cancer. Optimal is 1–2.
- Platelet count trends — a gradually declining platelet count can be an early sign of liver fibrosis or hypersplenism, both worth catching early.
Why "normal" isn't always optimal
Indian lab reference ranges for haemoglobin are often set wide — 12–17 g/dL for men. A haemoglobin of 12.5 g/dL in a man will show as "normal" on the report, but from a longevity and performance standpoint, it's suboptimal. You'd likely feel noticeably better at 15 g/dL.
Similarly, a WBC of 10,000 is technically within range, but studies show that WBC counts in the upper-normal range (above 7,500) are associated with higher cardiovascular risk over time. The sweet spot for longevity appears to be 4,500–6,500.
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