Question: do you have to fast before a sickle cell blood test?
Answer: How do you prepare for a sickle cell test? No preparation is required for the sickle cell test. However, receiving a sickle cell test within 90 days after a blood transfusion may lead to inaccurate test results. Transfusion can reduce the amount of hemoglobin S — the protein that causes SCD — in the blood.