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.
Department of Haematology, Imperial College Faculty of Medicine at St Mary's Hospital, and Department of Haematology, St Mary's Hospital, London, England.
Jason
J
Chow
Lorraine
L
Phelan
Barbara J
BJ
Bain
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