Evaluation of single-tube osmotic fragility as a screening test for thalassemia.
A single-tube osmotic fragility test has been proposed for thalassemia screening with a range of different concentrations of saline having been employed. We have compared the sensitivity and specificity of 0.32%, 0.34%, and 0.36% buffered saline, and on the basis of our findings, recommend the use of 0.36% saline. This gave definitely positive or equivocal results in 81 of 85 patients with beta thalassemia trait and in 4 of 4 with alpha(0) thalassemia trait. There were 14% false positive results in hematologically normal patients and 81% of the samples from patients with various variant hemoglobins gave positive results. The sensitivity was 95% and specificity 86%. The single-tube osmotic fragility test is potentially useful in under-resourced laboratories although it cannot replace automated red cell indices using electronic counters.
Chow
Jason
J
Department of Haematology, Imperial College Faculty of Medicine at St Mary's Hospital, and Department of Haematology, St Mary's Hospital, London, England.
Phelan
Lorraine
L
Bain
Barbara J
BJ
D005189:False Positive Reactions; D006446:Hemoglobin E; D006453:Hemoglobinopathies / Q000175:diagnosis; D006801:Humans; D008403:Mass Screening / Q000191:economics / Q000379:methods* / Q000592:standards; D009996:Osmotic Fragility; D012680:Sensitivity and Specificity; D012965:Sodium Chloride; D013789:Thalassemia / Q000175:diagnosis*; D017085:alpha-Thalassemia / Q000175:diagnosis; D017086:beta-Thalassemia / Q000175:diagnosis
D012965:Sodium Chloride; D006446:Hemoglobin E