Automated Dithionite Test for Rapid, Inexpensive Detection of Hemoglobin S and Non-S Sickling Hemoglobinopathies

Abstract

Automated adaptations of dithionite and urea—dithionite tube tests are accurate, reliable, inexpensive methods for detecting hemoglobin S. More than 3,000 individuals have been screened (120 determinations per hour; reagent cost, 2 to 4 cents per test). The dithionite reagent consists of potassium phosphate, sodium dithionite, and saponin. When S hemoglobin contacts this reagent, the red cells lyse, and the hemoglobin deoxygenates and sickles, forming a hydrophobic-bond-dependent nematic liquid crystal system that is manifested as turbidity. The resulting AutoAnalyzer curve is strikingly and diagnostically different from that produced by hemoglobin A in the same reagent. Specificity of the automated dithionite test may be enhanced by use of the automated urea—dithionite test, which consists of a specimen set of two aliquots: one traverses a dithionite line, the other a urea—dithionite line. A comparison of transmittance in the two lines yields typical diagnostic curves because the urea disperses the sickling, with a consequently increased transmittance over that of the dithionite aliquot. Methods are discussed for recognizing non-S sickling hemoglobins and a few other rare hemoglobinopathies.

Age Trends in the Prevalence of the Sickle Cell Trait

“…Specimens were collected in heparinized capillary tubes and mailed to the Albany laboratory for processing. Preliminary screening was done by lysing the red cells in a high-molarity phosphate buffer in the presence of dithionite, a technique which is a modification of the Itano solubility test (11)(12)(13). Under these conditions, hemoglobin S forms insoluble crystals that produce a turbid solution.…”

Thalassemia Syndrome

“…Therefore, availability of more modern instrumentation that can provide more precise information with little requirement of an experienced operator and less usage of toxic chemicals diminishes the use of some of these conventional techniques such as DST and ART. (Fairbanks, 1980, Nalbandian et al, 1971, Greenberg et al, 1972.…”

Traço Falciforme: Estudo Comparativo De Técnicas Laboratoriais Utilizadas Para a Triagem Da Doença

“…A escolha da metodologia laboratorial adequada para a identificação das hemoglobinas humanas anormais depende da suspeita clínica para a sua maior eficácia, sendo importante o conhecimento pelo laboratorista de suas reais aplicações e possíveis limitações. São ferramentas úteis de diagnóstico, além da avaliação dos índices hematimétricos; a eletroforese qualitativa de hemoglobina em acetato de celulose em pH alcalino; a dosagem de hemoglobina fetal; o teste de falcização; o teste de solubilidade para a hemoglobina S, entre outras técnicas úteis para o diagnóstico das modificações estruturais da hemoglobina (LIMA, 1984;NALBANDIAN, 1971).…”