Utility of Cryohemolysis Test in the Diagnosis of Hereditary Spherocytosis.

Diagnosis of Hereditary spherocytosis (HS) often requires time-consuming and/or expensive tests. Cryohemolysis test (CHT) is a simple and easy to perform test with high predictive value for HS diagnosis. In this prospective study, we evaluated the diagnostic utility of CHT for the diagnosis of HS. We included 60 suspected HS patients, 18 patients with Autoimmune hemolytic anemia (AIHA) and 120 healthy controls. Among the 60 suspected cases, there were 36 HS cases and 24 with other hemolytic anemias. The mean CHT (%) ± SD for controls, AIHA, other hemolytic anemias, and HS was 6.63 ± 2.79, 6.79 ± 4.36, 6.61 ± 2.76 and 26.7 ± 8.9, respectively. The CHT % was significantly higher in HS group when compared to controls ( p  =  < 0.0001), AIHA ( p  =  < 0.0001) and other hemolytic anemia groups ( p  =  < 0.0001). At a CHT cut off of > 18.3%, the sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of HS in our study were 97.1%, 94.4%, 97.2% and 90.3%, respectively. CHT is a simple and sensitive test for the diagnosis of HS but remains underutilized. The addition of CHT in the diagnostic workup of HS will be very useful, especially in a resource limited setting.