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Thymol Turbidity and Thymol Flocculation Tests As a Screening Technic to Detect Blood Donors Carrying the Hepatitis Virus

1961; Wiley; Volume: 1; Issue: 5 Linguagem: Inglês

10.1111/j.1537-2995.1961.tb00061.x

1537-2995

John B. Alsever, James D. Barger,

Hepatitis B Virus Studies

Six‐month follow up study showed a hepatitis case rate of 1.55% in 905 patients receiving “abnormal” blood and 0.88% in 1,480 receiving nothing but “normal” blood, based on screening at the 95% confidence level of 8.0 T.T. units in clear sera and in lipemic sera of 8.0 units or more with a positive flocculation test (from studies of 52,662 consecutive donors reported in Part I). Significantly, screening at the 99% level gave less specific results: a 1.06% rate in controls and 1.42% in the test cases. The observed differences in rates are not statistically significant: twice the standard error of the difference in percentages is 0.9%, the Chi Square test showed P = 0.15 (at 95%) and 0.70 (at 99%). The donor (unit) case rates were essentially identical (0.346) in the test series and in the controls at both screening levels and the difference in hepatitis case rates was exactly proportional to the difference in the average donor exposure of the two groups at each screening level. The two groups of cases received 14% of the total blood units available and this was representative of the total available as judged by the mean T.T. values of blood received by the study cases. There was a steady increase in the hepatitis case rate from 0.6% in single unit transfusions (29% of cases) to 2.6% when four units were used, with a rate of 1.1% in those receiving five units or more (19%), suggesting the risk of hepatitis is maximal in transfusions of four or more units. Cogent reasons are presented for abandoning attempts to use nonspecific liver function tests for donor screening to eliminate significant numbers of donor carriers.