No abstract

The Coccidioides EIA has potential to be useful in the rapid diagnosis of more-severe forms of coccidioidomycosis.

Physicians should be alerted that infections with Coccidioides species may cause positive Histoplasma antigen test results. There is potential for the use of this test in the diagnosis of coccidioidomycosis by taking advantage of this observed cross-reactivity. The greatest benefit appears to be in the population of seriously ill patients with acute pneumonia who live in areas that are endemic for Coccidioides infection.

Between 1959 and 1976, 34 patients were seen in Hawaii with eosinophilic meningitis. Angiostrongylus cantonensis was recovered from two of these patients. The remaining cases were presumed to be due to this parasite because of clinical and epidemiologic findings. The most likely source of infection for eight patients was ingesting raw terrestrial snails or slugs, and for six patients eating raw or poorly cooked crustaceans. Patients typically presented with severe headache; neck stiffness and fever were usually mild or absent. Paresthesias were noted by most adults. The cerebrospinal fluid (CSF) cell count ranged from 150 to 1500 leukocytes per cubic millimeter, with a mean eosinophil percentage of 38. CSF IgE levels were not abnormal in four patients so studied. Although two deaths occurred, the illness was typically self-limited, resolving completely with no specific treatment.

The clinical observation has been made that there might be an unacceptable number of false-positive enzyme immunoassay (EIA) test results for IgM among persons suspected of having coccidioidomycosis. Patients with a positive result for IgM by EIA are thought to have a diagnosis of acute coccidioidomycosis. However, this study found that 82% of patients with an IgM-positive and IgG-negative EIA result did not have coccidioidomycosis.The Premier Coccidioides enzyme immunoassay (EIA; Meridian Bioscience, Inc., Cincinnati, OH) is a commercially available test used for the serological diagnosis of coccidioidomycosis. Clinical laboratories use that EIA for the detection of both IgM and IgG antibodies directed against Coccidioides. A positive EIA result for IgM is believed to be associated with the initial antibody response seen in an acute Coccidioides infection (3). The EIA test is also used to determine the presence of IgG antibody, which is diagnostic of an infection with Coccidioides. Clinicians use the various IgM and IgG antibody responses to determine the presence or the absence of an acute or a chronic Coccidioides infection (5).The Premier assay may be subject to false-positive results for IgM, as suggested by prior studies (2, 3). In contrast, those clinical and serological studies found a good correlation between a positive result for IgG by the Premier assay and infection with Coccidioides.A false-positive EIA result for IgM occurs when patients are thought to be experiencing acute coccidioidomycosis but do not have a Coccidioides infection. Clinical observations have raised concern that there may be an unacceptable number of false-positive IgM results with the Premier assay. A false-positive serological result can create clinical problems, resulting in the treatment of patients for a disease that they do not have or thinking that the patient has coccidioidomycosis and missing another medical condition. The study described here was done to correlate clinical findings and serological results for patients who had a positive result for IgM and a negative result for IgG by the Premier Coccidioides EIA. CASE REPORTA man with chronic lung disease and an aortic valve replacement who was receiving warfarin was admitted for hemoptysis. A month previously he had been diagnosed as having acute pulmonary coccidioidomycosis on the basis of positive results for IgM and negative results for IgG by EIA. He was placed on oral fluconazole at 400 mg daily. Fluconazole is known to alter the metabolism of warfarin. The fluconazole caused an increase in the anticoagulation effect of warfarin, which led to bleeding and hemoptysis. The problem resolved following discontinuation of the fluconazole and the finding of no confirmatory evidence for coccidioidomycosis. MATERIALS AND METHODSThe laboratories at John C. Lincoln Hospitals (the clinical laboratory) have routinely used the Premier EIA kit since 1995 for the detection of IgM and IgG antibodies in patients suspected of having an infection due to Coccidioides. The EIAs were per...