Most first-time donors overestimate how strict the eligibility bar is. In India, the basic checklist is simple: you need to be between 18 and 65 years old, weigh at least 45 kg, and have a hemoglobin level of at least 12.5 g/dL. Blood banks check hemoglobin on the spot with a quick finger-prick test before you're allowed to donate, so there's no need to get it tested in advance.

Gaps between donations matter too. Whole blood donors need to wait at least 90 days (roughly three months) between donations, while platelet donors on an apheresis machine can donate more frequently, sometimes every two weeks, up to a yearly limit. Women are generally asked to wait a little longer between donations than men, and pregnancy, recent childbirth, or breastfeeding are temporary deferrals rather than permanent exclusions.

A handful of things cause short-term deferral rather than lifetime disqualification: a recent tattoo or piercing (usually a 6–12 month wait), a recent minor surgery, an ongoing cold or fever, or having taken certain medications in the last few days. Chronic conditions like well-controlled diabetes or hypertension usually don't rule you out either — when in doubt, the blood bank's screening staff will ask a short questionnaire and make the call at the camp itself, so it's always worth showing up and asking rather than assuming you don't qualify.