ABSTRACT
This study was designed to determine the ability of a hemoglobinopathy screening protocol
involving sickle solubility testing and red blood cell (RBC) indices to identify at-risk
pregnancies. Retrospective chart review of all patients registering for prenatal care
at the New York Hospital/Cornell Medical Center prenatal clinic in 1996 was the study
design. All patients had RBC indices as well as hemoglobin electrophoresis. RBC indices
of those with normal and abnormal electrophoreses were compared. Comparison of protocols
involving universal hemoglobin electrophoresis and selective use of hemoglobin electrophoresis
were compared. Student's f-test was used for statistical analysis. There were 36 carriers
of hemoglobinopathy traits in 631 patients screened (5.7%). Four (three with hemoglobin
C trait and one with hemoglobin D trait) had normal RBC indices and presumably would
have had negative sickle solubility testing. The sensitivity, specificity, positive
predictive value (PPV), and negative predictive value (NPV) of a protocol with selective
use of hemoglobin electrophoresis would have been 88.9, 79.4, 20.8, and 99.2%, respectively.
Cost analysis reveals a difference of $11,384 or $18/patient less in a protocol with
selective use of hemoglobin electrophoresis. Although a protocol involving solubility
testing with RBC indices will not identify every carrier of a hemoglobinopathy trait,
it may be appropriate in some populations.
Keywords
Hemoglobinopathy - genetic screening - prenatal diagnosis
