A blood test is one of the cheapest, fastest and most powerful tools in medicine — yet most people only get one when something is already wrong. This short guide covers the warning signs that should trigger a test today, the routine screening schedule every adult should follow, and the small handful of tests that give the biggest picture of your health.
- Persistent fatigue, unexplained weight change or frequent infections deserve a blood test.
- Every adult should screen at least once every 1–2 years, even when feeling fine.
- CBC, HbA1c, lipid profile, TSH and vitamin D cover most everyday concerns.
- Fasting rules only apply to certain tests — your clinic will always tell you.
Symptoms that mean 'test now'
- Persistent tiredness that sleep does not fix.
- Unexplained weight loss or gain over three months.
- Frequent infections, slow-healing wounds or gum bleeding.
- New-onset headaches, dizziness or palpitations.
- Recurring urinary infections or excessive thirst.
- Menstrual changes lasting more than two cycles.
Routine screening by age
In your 20s and 30s, a basic annual profile — CBC, blood sugar, lipids, TSH and vitamin D — is enough for most healthy adults. From your 40s onwards, add HbA1c, liver and kidney function, and a urine routine. Above 50, include a PSA for men and thyroid antibodies for women with symptoms. Diabetics and hypertensives should test every 3–6 months regardless of age.
The five tests worth doing even when you feel fine
- Complete Blood Count (CBC) — anaemia, infection, platelet trends.
- HbA1c — a three-month view of blood sugar.
- Lipid profile — cholesterol and cardiac risk.
- TSH — thyroid function, especially for women.
- Vitamin D — widely deficient in Indian adults.
Frequently asked
Have a personal question about this?
Book a short consultation with Dr. B.P. Singh at Sanjeevani Clinic Pvt. Ltd., or WhatsApp us and we will guide you.