Sri Lanka Blood Donation Eligibility Checker

The checker runs your answers through thirteen NBTS donor selection rules in order. Each rule returns one of three outcomes: pass, temporary deferral (with a specific next-eligible date), or permanent deferral. The final verdict combines them with two simple rules: any permanent deferral wins outright; otherwise the next-eligible date is the latest of all temporary deferrals. The rule list below is the same array the calculator uses — there is no hidden logic.

• Age. First-time donors must be 18–60; repeat donors are accepted up to 65. Under-18s are temporarily deferred until their 18th birthday; over-65 are permanently deferred for whole-blood donation.
• Body weight. Minimum 50 kg for a 450 mL whole-blood donation. Below this the safe collected volume is too low and the donor is at increased risk of hypovolemic reactions.
• Hemoglobin. Males ≥ 12.5 g/dL, females ≥ 12 g/dL (NBTS, aligned with WHO). Low Hb triggers a 90-day deferral so the donor can recover iron stores before re-screening.
• Inter-donation interval. Whole-blood donors must wait at least 120 days between donations to allow iron stores and red cells to recover (NBTS).
• Pregnancy and breastfeeding. Pregnant donors and donors within 12 months postpartum (or while breastfeeding) are deferred to protect maternal iron stores and infant nutrition (NBTS, WHO).
• Tattoo, piercing, or acupuncture. 365-day deferral from the date of any tattoo, piercing, or acupuncture procedure — the window covers blood-borne infection sero-conversion (NBTS).
• Major surgery. 365-day deferral after major surgery, to cover both recovery and the residual risk window from any blood products received intra-operatively (NBTS).
• Recent dental work. 7-day deferral after extractions, root canal, or other invasive dental work (transient bacteraemia risk).
• Antibiotics or recent infection. 14-day deferral after completing antibiotics or after the resolution of any acute infectious illness.
• Travel to malaria-endemic areas. 365-day deferral after return from any malaria-endemic country or district (NBTS, aligned with WHO blood-safety guidance).
• COVID-19 vaccination. 7-day deferral after any dose of a COVID-19 vaccine, provided the donor is symptom-free.
• Live-attenuated vaccine. 28-day deferral after live-attenuated vaccines (MMR, varicella, yellow fever, oral polio, oral typhoid).
• Blood-borne infection diagnosis. A self-reported diagnosis of HIV, hepatitis B, hepatitis C, or syphilis is a permanent deferral from whole-blood donation (NBTS, WHO).

Why these rules and not someone else's

Every threshold is taken from a single primary source: the National Blood Transfusion Service of Sri Lanka. NBTS criteria are themselves aligned with WHO blood-safety guidance, which is why the World Health Organisation document appears as a secondary citation on a handful of rules — but where NBTS is stricter than WHO, NBTS wins. The checker encodes the public, written rules; centre medical officers have additional clinical discretion on the day. If the checker says you are clearly eligible, you almost always are. If it defers you, ring the centre before travelling — they can confirm whether the deferral period actually applies to your case.

Cross-check and credibility

For each session the tool runs the rule engine twice. The first pass uses any specific dates you entered (tattoo on this day, surgery on that day, last donation on that day) and computes the earliest next-eligible date from each. The second pass discards those dates and conservatively applies every deferral period from today — the worst case if you cannot remember exactly when something happened. If both passes agree on the verdict, the result is robust to date-precision errors and that is shown as a green "methods agree" badge below the verdict. If they disagree, the difference is highlighted and the recommendation is to confirm with the centre medical officer.

What the checker does not screen for

Three categories are deliberately out of scope. First, apheresis-only eligibility — plasma, platelet, and double red-cell donations use different and usually higher weight and hemoglobin thresholds, and the inter-donation interval is much shorter (typically 7–14 days for plasma). Second, conditions you have not been diagnosed with — the tool asks about self-reported HIV/HBV/HCV/syphilis status only and does not attempt to screen for undisclosed conditions. Third, drug interactions beyond the broad "currently on antibiotics" gate; NBTS maintains a multi-page medication deferral matrix that is worked through manually at the centre. If your daily medication list is non-trivial, bring it on paper and let the centre check it.

Edge cases handled explicitly

(1) Donors aged 16–17 are not permanently deferred — the checker returns a temporary deferral that expires on their 18th birthday, so the eligibility calendar shows the right date even years out. (2) When two or more temporary deferrals stack (e.g. a tattoo and a recent vaccine), the maximum next-eligible date wins and every contributing rule is listed in the itemised reasons. (3) When the donor enters a procedure flag but cannot remember the exact date, the deferral is applied from today rather than from the procedure date, which is the conservative interpretation NBTS itself uses in uncertain cases. (4) Weight, hemoglobin, and date inputs validate before the rule engine runs, so a typo like 4.7 kg or 1.31 g/dL surfaces as a specific error instead of being silently coerced.

Three scenarios that map to the most common Sri Lankan walk-in profiles. Try them in the checker above — the itemised reasons should match each line below.

• National Blood Transfusion Service of Sri Lanka — official site & donor selection criteria
• Ministry of Health, Sri Lanka — donor selection and donor care guidelines
• WHO — Blood Donor Selection: Guidelines on Assessing Donor Suitability for Blood Donation (2012)

Last cross-checked against NBTS sources on 2026-05-17. Reviewed after any NBTS guideline revision.