Reaccion de doble difusion en agar con deteccion del arco 5o. en el diagnostico de la hidatidosis / Double-diffusion reaction on agar with arc 5 detection i the diagnosis of hydatidosis

ABSTRACT

The performance of double-diffusion reaction on agar with arc 5 detection (DD5) in the diagnosis of hydatidosis in man is analyzed in this study. A review was made of the clinical histories of 226 patients who had been seen between 1980 and 1986 at a hospital in Santiago, Chile, with manifestations suggestive of this disease. In 98 cases the diagnosis of hydatidosis was confirmed surgically. In 55 of these cases (56.1 per cent), the DD5 was positive. The test was least sensitive for pulmonary hydatidosis (36 per cent), while the reaction was positive for 62.7 per cent of the patients with a single cyst of multiple liver cysts, and for 64.7 per cent of those who had hydatid cysts in more than one organ. In the 128 non-hydatid patients who had neoplasms, benign tumors, cirrhosis of the liver, or other diseases, no false positive results were observed when the criterion for positivity was either the presence of arc 5 or of three or more precipitation bands. According to the results of this study, the use of DD5 for the diagnosis of hydatidosis in clinically selected individuals provides a highly specific test. The positive predictive value of the test in the study was 99.1 per cent. It should also be noted, however, that negative results with DD5 do not invalidate the presence of hydatid cysts in a patient especially in pulmonary cases