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We developed a colorimetric microtiter plate polymerase chain reaction enzyme immunoassay (PCR-EIA) for the detection of Histoplasma capsulatum in urine. The specificity of the PCR assay was confirmed using H. capsulatum (positive control) and Blastomyces dermatitidis (negative control) isolates. The analytical sensitivity of the PCR assay was determined by testing urine samples spiked with freshly grown H. capsulatum organisms and was 2 yeasts per reaction in urine and 0.2 yeasts per reaction in urine sediment after centrifugation. Fifty-one urine specimens positive for H. capsulatum antigen and 25 urine specimens from healthy volunteers were tested blindly. Patient specimens also were cultured for H. capsulatum. The PCR assay was positive in 4 (7.8%) of 51 urine specimens containing antigen and negative in urine specimens from healthy volunteers. The positive PCR results occurred in 4 of 5 urine specimens that were positive by culture, and each exhibited high level of antigenuria (>20 U). Urine cultures were not positive in 24 urine specimens with an antigenuria of 1-19.9 U, but were positive in 5 of 27 urine specimens with antigenuria >20 U. Thus, positive PCR results in urine specimens correlate with positive culture results, but not with antigenuria. The low sensitivity of this PCR assay in urine limits its use in the diagnosis of disseminated histoplasmosis.

Blastomycosis is a serious and potentially fatal infection, and diagnosis can be difficult at times. We evaluated the diagnostic utility of a commercially available assay for detection of Blastomyces dermatitidis antigen, recently modified to permit quantitation, in subjects with newly diagnosed blastomycosis. Twenty-three of 27 (85.1%) subjects had detectable B. dermatitidis antigenuria. In 2 of these 23, positive results were obtained after concentration of the urine specimen. Nine of 11 (81.8%) subjects had detectable B. dermatitidis antigen in serum, including 3 subjects with negative results before treatment of serum with ethylenediaminetetraacetic acid (EDTA) and positive results after EDTA treatment. B. dermatitidis antigen was not detected in specimens from 50 control subjects but was detected in 15 patients with histoplasmosis. B. dermatitidis antigen was detected in most of the patients with blastomycosis and can be a useful tool for timely diagnosis.

Histoplasmosis is a common infection in endemic regions of North and Latin America, causing a broad spectrum of clinical findings. The diagnosis may be missed or delayed because histoplasmosis is not considered in the differential. A battery of serologic and mycologic tests may be used for the diagnosis, but each has advantages and limitations. Antigen detection may be particularly helpful for making a rapid diagnosis in patients with more extensive infection. The purpose of this review is to provide a comprehensive discussion of the role of antigen detection in the diagnosis of histoplasmosis, to provide the clinician and laboratory worker with a fuller understanding of the benefits and limitations of this useful laboratory method. This report is based soley upon the experience at the Histoplasmosis Reference Laboratory, and can not be used in interpretation of results of Histoplasma antigen testing done at other laboratories.

An enzyme-linked immunosorbent assay (ELISA) for measles-specific immunoglobulin M (MIgM) was developed for use as a rapid diagnostic test for acute measles. A titer greater than or equal to 1:20 in both the acute and convalescent sera was present in 100% of patients with measles and was diagnostic of acute measles infection in children. Interference by rheumatoid factor (RF) was avoided by pretesting sera for RF and absorption with aggregated gamma globulin. Ion exchange separation of IgM and IgG should eliminate RF interference. The ELISA MIgM assay can easily be used in any laboratory for the serologic confirmation of measles infection.

A patient with disseminated histoplasmosis is described in whom blood cultures were negative using conventional media but positive for Histoplasma capsulatum using the DuPont Isolator system. Fungal blood culture methods are discussed.

We previously reported that 80% of patients with serogroup 1 Legionella pneumophila pneumonia excrete detectable quantities of specific antigens in their urine. The purpose of this study was to determine whether specific antigens can be detected in urine from patients with serogroup 4 L . pneumophila pneumonia. Antisera were prepared in 15 rabbits and used to set up 25 solid-phase radioimmunoassays. The best of these assays detected specific antigens in urine from 4 of 5 patients with culture-proven serogroup 4 infections and from 1 of 2 patients with culture-proven serogroup 10 infections. None of 100 control specimens was positive in the assays. The antigens from serogroup 4 and 10 infections behaved differently in the assays, suggesting that they are not identical molecules. This study demonstrates that it is possible to detect specific antigens in the urine of patients with serogroup 4 L . pneumophila pneumonia. This may be a useful method for diagnosing these infections rapidly.