Hb
S – Screening Tests - II
Screening
tests for Hb S
Solubility tests
Sodium dithionite
A drop of blood is
mixed with saponin which lysis the cells
releasing hemoglobin which reacts with dithionite to form crystals (if Hb S) thus
increasing turbidity
Tube layering
solubility test
Blood is added to a
tube containing an organic and an aqueous layer and depending on the type
of Hb present determines color changes in various layers
Specimen requirements:
EDTA, heparin, or
sodium citrate less than 3 weeks old