• The results of precipitin and complement-fixation tests have been analyzed in 5,579 cases of nondisseminating and 722 cases of disseminated coccidioidal infection. In the nondisseminating cases, the skin test becomes positive first, and serologic tests should not be requested unless and until the skin test is shown to be positive. The precipitin appears later, the proportion of positive tests reaching a maximum of 91% in the third week. The complement-fixing antibodies appear more slowly than the precipitins and persist longer. In the disseminated cases, the complement-fixation test was positive in all but two instances. The titer of complement fixation generally reflected the severity of the infection. When the titer regressed, the prognosis was reassuring.
The complement-fixing antibody appears in the spinal fluid only if meningitis develops; it is therefore diagnostic. However, the antibody has been found in the umbilical cord blood in cases of maternal coccidioidomycosis when there was no evidence of infection in the infant.