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After taking capillary blood samples, we used the sickling test and paper and agar gel electrophoresis to diagnose the sickle cell trait and sickle cell anaemia in children in Zambia. The results of a survey of 1,707 children under the age of 4 years, not suspected of having sickle cell anaemia, are presented. A diagnosis was made with confidence in children over 3 weeks of age. This simple screening system can be easily introduced for the large scale examination of children attending postnatal or paediatric clinics. The size and seriousness of the problem of sickle cell anaemia certainly merit this in African children, wherever medical supervision is available. A differential mortality between children of haemoglobin AA and haemoglobin AS types has been confirmed. The possible role of the sickling trait in protecting against general infections as well as malignant malaria is discussed.

IN 1955 Rucknagel et al.1 described a new abnormal hemoglobin in a Negro family in North Carolina. This hemoglobin, designated "I", migrated more rapidly than normal hemoglobin on filter-paper electrophoresis at pH 8.6, and constituted about 20 per cent of the total hemoglobin present. The following report concerns a patient with a similar I-A electrophoretic hemoglobin pattern in whom the I hemoglobin constitutes 70 per cent of the total hemoglobin. Despite the absence of S hemoglobin in the red cells of this patient, the sodium metabisulfite sickling test was found to be positive.2 Clinical Data J.W., a twenty-five-year-old Negro woman, . . .

Loh, Wei-Ping: Evaluation of a rapid test tube turbidity test for the detection of sickle cell hemoglobin. Amer. J. Clin. Path. 55: 55-57, 1971. A rapid turbidity test for detection of hemoglobin S is described and compared with the standard metabisulfite sickling test and electrophoresis. On the basis of 2,355 patients studied during an 18-month period, the new rapid test was found to be accurate and easy to perform. The test requires only 5 min. to complete. Routine use of this test for Negro patients before major surgery helped in the selection of anesthesia and prevention of unexpected deaths due to hypoxia. The test is expected to be extremely valuable for mass screening when rapid detection of hemoglobin S is desirable. THREE YEARS AGO I encountered three un­ expected surgical deaths in young Negroes who dietl during or immediately after major abdominal surgery. Postmortem ex­ amination of two of the three patients revealed no clear-cut cause of death. Hemo­ lytic reactions and vascular complications due to prolonged hypoxia in the presence of sickle cell hemoglobin (Hb-S) were sus­ pected to be factors in the fatal outcome. It was clear that rapid detection of such abnormal hemoglobin before major surgery would be helpful in the selection of anes­ thesia anil in prevention of hypoxia in order to avoid unexpected surgical deaths. Deoxygenated (reduced) Hb-S is less solu­ ble than oxygenated Hb-S and less soluble than reduced normal adult hemoglobin

To the Editor:— The paper of Schneider, Alperin, and Lehmann (202:419, 1967) pointed out the occasional difficulties and pitfalls of the standard sickling test performed in the clinical laboratory. A much simpler and more reliable test for the clinical laboratory is the slideelution test which we developed a few years ago (Blood24:198, 1964). This test is based on the fact that hemoglobin S is insoluble in high molar phosphate buffer. Blood smears are prepared from capillary blood in the same way as for staining, but the unstained slides are placed into Coplin jars filled with 50 ml of 2.4 O M phosphate buffer (20.9 g/100 cc of K2HPO4and 16.3 g/100 cc of KH2PO4; the solution is stable and we have used it for longer than three months after preparation). Just prior to the placement of the slide a small amount