Serologic evidence of the postoperative persistence of hydatid cysts in man.

The sensitivity of the haemagglutination, complement-fixation and indirect fluorescent antibody tests in the diagnosis of primary and recurrent hydatid disease is presented. In the first, diagnostic titres were obtained in 90% of 50 patients with hepatic and 64%, 60%, and 68% of 25 patients with pulmonary cysts, respectively. In the postoperative study of 62 patients, elevated titres of HA, CF and IFA antibodies in 30 led to the presumptive diagnosis of recurrent disease, confirmed later by radiological and surgical follow-ups. In the 32 others the proportion of positive reactors was 29%, 6% and 28% in HA, CF and IFA tests. These patients had no detectable cysts. This indicates that in postoperative patients a negative CF test may be of a better prognostic value in indicating absence of cysts than the HA and IFA tests.