What to expect from a blood test for sickle cell disease

Laboratory testing can examine the haemoglobin proteins in red blood cells. The pattern may support a diagnosis of sickle cell disease, sickle cell trait, another haemoglobin condition, or no abnormal haemoglobin detected. A blood count may add information about the red cells. Some results need confirmation with a second method, especially after a recent transfusion or when the result does not fit the clinical picture.

Tell the clinician about family history, previous transfusions, pregnancy, and any earlier haemoglobin testing. Ask how results will be shared and whether relatives or a partner may benefit from counselling. The sample usually needs no special preparation. Apply pressure afterward and mention continuing bleeding or marked swelling at the collection site.

Seek urgent help for severe pain, difficulty breathing, chest pain, sudden weakness, confusion, a high fever, or unusual sleepiness, particularly if sickle cell disease is known or suspected. These symptoms require immediate clinical assessment and should not wait for laboratory communication.

Ask whether the test is checking for disease, carrier status, or both; whether transfusion could affect interpretation; and whether confirmation is needed. Ask when the result will be explained and where to get genetic counselling if relevant.