[The human basophils degranulation test (HBDT). Leucoconcentration and statistical calculation applied to the degranulation rate (author's transl)].

The technique using hemolysis and vital coloration described by Benveniste permits the human basophils to be studied in immediate type allergies : HBDT. In almost 25% of the cases, the test cannot be carried out because the basophils are less than 20 per mm(3). In 700 but one case, the HBDT could be carried out using a leucoconcentration technique by means of a 100 to 200 g centrifugation of 10 mn duration, followed by tangential extraction, thus obtaining an increased number of basophils. The authors were lent to apply a statistical calculation to a significant degranulation rate due to the number of observable cells by means of an unilateral statistical test suggesting a distribution according to Poisson's law. Thus tests are interpreted more rapidly and are more reliable. On the other hand, comparison with the results obtained with or without leucoconcentration in different types of allergies due to reagins (drugs, hymenoptera, foods) do not show any cellular fragilization. It may be concluded to the reliability of the degranulation observed in presence of an antigen.