HbF Haemoglobin Foetal Test

Fetal hemoglobin or foetal hemoglobin is the main oxygen transport protein in the human fetus during the last seven months of development in the uterus and persists in the newborn until roughly 6 months old. Functionally, fetal hemoglobin differs most from adult hemoglobin in that it is able to bind oxygen with greater affinity than the adult form, giving the developing fetus better access to oxygen from the mother’s bloodstream. The results revealed that HbF was highest (98%) at birth, decreasing at 5% per week till 6 months when it wane off. Ten infants aged 6 – 12 months had HbF persisting at a level of 10% or more. Adult patients examined showed proportions of their sickle cell types as forming 51%, AC 20%, SS 19%, and SC 10%. An SS adult patient with mild sickle cell crisis had an ASF father who had no crisis and a mother and brother with AS each who had severe crisis.

Parents may wish to explain the blood-drawing procedure to older children to help prepare them for the slight discomfort they will experience. Testing for fetal hemoglobin requires that a blood sample be drawn from the child. No preparation is needed before performing fetal hemoglobin tests, and fasting (nothing to eat or drink for a period of hours before the test) is not required. Proper identification and careful handling of the child are important when a blood sample is being obtained for testing. A site, usually the heel on an infant and a finger on an older child, is chosen by the phlebotomist who will draw the blood.

When fetal hemoglobin production is switched off after birth, normal children begin producing adult hemoglobin (HbA). Children with sickle-cell disease instead begin producing a defective form of hemoglobin called hemoglobin S which aggregates together and forms filaments that cause red blood cells to change their shape from round to sickle-shaped. If fetal hemoglobin remains the predominant form of hemoglobin after birth, the number of painful episodes decreases in patients with sickle-cell disease. Hydroxyurea promotes the production of fetal hemoglobin and can thus be used to treat sickle-cell disease

Mix blood with a small amount of distal water which will lead to hemolytic. Due to hemolytic, there will be the release of free hemoglobin. Now centrifuge the sample for several minutes. Mix 5 mL of supernatant (pink in color) with 1mL of 1% NaOH. Check the color after 2 minutes: Fetal hemoglobin (HbF) will be pink.