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The sensitivity of antigen detection in disseminated histoplasmosis is higher in immunocompromised patients than in immunocompetent patients and in patients with more severe illness. The sensitivity for detection of antigenemia is similar to that for antigenuria in disseminated infection.

Tests for Chlamydia trachomatis and Neisseria gonorrhoeae, which can provide results rapidly to guide therapeutic decision-making, offer patient care advantages over laboratory-based tests that require several days to provide results. We compared results from the Cepheid GeneXpert CT/NG (Xpert) assay to results from two currently approved nucleic acid amplification assays in 1,722 female and 1,387 male volunteers. Results for chlamydia in females demonstrated sensitivities for endocervical, vaginal, and urine samples of 97.4%, 98.7%, and 97.6%, respectively, and for urine samples from males, a sensitivity of 97.5%, with all specificity estimates being >99.4%. Results for gonorrhea in females demonstrated sensitivities for endocervical, vaginal, and urine samples of 100.0%, 100.0%, and 95.6%, respectively, and for urine samples from males, a sensitivity of 98.0%, with all estimates of specificity being >99.8%. These results indicate that this short-turnaround-time test can be used to accurately test patients and to possibly do so at the site of care, thus potentially improving chlamydia and gonorrhea control efforts. Chlamydia trachomatis and Neisseria gonorrhoeae are the agents of the two most prevalent bacterial sexually transmitted infections (STIs) reported to the Centers for Disease Control and Prevention (CDC), accounting for Ͼ1.6 million reported infections in the United States in 2010 (1). The CDC estimates that STIs cost the health care system $1.5 billion annually. Since these infections, especially chlamydia, are most often asymptomatic, the CDC recommends yearly screening for chlamydia in all sexually active women aged 16 to 25 years. Further, since coinfections are common, most diagnostic test platforms assay for both organisms. Nucleic acid amplification tests (NAATs) are now recommended by the CDC (2) as the tests of choice; however, current NAATs are classified as being of high or moderate complexity and might take 1 to 2 days for results to become available. New assays and new platforms that provide results at the time of patient visits are urgently needed, since many patients do not return for their results when laboratory-based tests that require several days for their results are performed (3, 4).The Cepheid GeneXpert CT/NG (Xpert) assay is a rapid (Ͻ2 h to results) NAAT assay that can be performed in on-site laboratories. The assay detects the DNA of C. trachomatis and N. gonorrhoeae from endocervical, vaginal, and urine specimens of females, as well as from urine specimens of males, from both symptomatic and asymptomatic individuals. The Xpert test is performed using a modular cartridge-based platform for testing each specimen by nucleic acid amplification, and it can process from 1 to 96 specimens in Ͻ2 h with easy-to-use cartridges that minimize processing steps and contamination. This study compares the clinical performance (as measured by sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV]) of the Xpert assay to the patient infection status (PIS)...

A multicenter clinical trial assessed the performance of the Cepheid Xpert C. difficile assay on stool specimens collected from patients suspected of having Clostridium difficile infection (CDI). A total of 2,296 unformed stool specimens, collected from seven study sites, were tested by Xpert C. difficile enrichment culture followed by cell culture cytotoxicity testing of the isolates (i.e., toxigenic culture with enrichment) and the study sites' standard C. difficile test methods. The methods included enzyme immunoassay (EIA), direct cytotoxin testing, and two-and three-step algorithms using glutamate dehydrogenase (GDH) screening followed by either EIA or EIA and an in-house PCR assay. All C. difficile strains were typed by PCR-ribotyping. Compared to results for toxigenic culture with enrichment, the sensitivity, specificity, and positive and negative predictive values of the Xpert assay were 93.5, 94.0, 73.0, and 98.8%, respectively. The overall sensitivity of the EIAs compared to that of enrichment culture was 60.0%, and the sensitivity of combined GDH algorithms was 72.9%; both were significantly lower than that of Xpert C. difficile (P < 0.001 and P ‫؍‬ 0.03, respectively). The sensitivity of the EIA was significantly lower than that of the Xpert C. difficile assay for detection of ribotypes 002, 027, and 106 (P < 0.0001, P < 0.0001, and P ‫؍‬ 0.004, respectively, Fisher's exact test), and the sensitivity of GDH algorithms for ribotypes other than 027 was lower than that for Xpert C. difficile (P < 0.001). The Xpert C. difficile assay is a simple, rapid, and accurate method for detection of toxigenic C. difficile in unformed stool specimens and is minimally affected by strain type compared to EIA and GDH-based methods.

OBJECTIVE Vaginitis may be diagnosed as bacterial vaginosis, vulvovaginal candidiasis, trichomoniasis, or coinfection. A new molecular test assays the vaginal microbiome and organisms that cause three common infections. The objective of the trial was to evaluate the clinical accuracy of the investigational test for vaginal swabs collected by patients (self) or clinicians. The primary and secondary outcomes were to compare the investigational test with reference methods for the three most common causes of vaginitis and compare clinician-collected with self-collected swabs. METHODS We conducted a cross-sectional study in which women with symptoms of vaginitis were recruited at ten clinical centers and consented to the investigation between May and September 2015. The woman collected a vaginal swab, sheathed, and then handed it to the clinician. These swabs were to evaluate how self-collected swabs compared with clinician-collected swabs. The clinician collected an investigational test swab and reference test swabs. From 1,740 symptomatic patients, clinician-collected and self-collected vaginal swabs were evaluated by the molecular test and six tests. The reference methods for bacterial vaginosis were Nugent’s score and Amsel’s criteria for intermediate Nugent results. The reference methods for Candida infection were isolation of any potential Candida microorganisms from inoculation of two culture media: chromogenic and Sabouraud agar and sequencing. The reference methods for trichomoniasis were wet mount and culture. RESULTS For clinician-collected swabs, by reference methods, bacterial vaginosis was diagnosed in 56.5%, vaginal candidiasis in 32.8%, trichomoniasis in 8%, and none of the three infections in 24% with a coinfection rate of 20%. The investigational test sensitivity was 90.5% (95% confidence interval [CI] 88.3–92.2%) and specificity was 85.8% (95% CI 83.0–88.3%) for bacterial vaginosis. The investigational test sensitivity was 90.9% (95% CI 88.1–93.1%) and specificity was 94.1% (95% CI 92.6–95.4%) for the Candida group. Sensitivity for Candida glabrata was 75.9% (95% CI 57.9–87.8%) and specificity was 99.7% (95% CI 99.3–99.9%). Investigational test sensitivity was 93.1% (95% CI 87.4–96.3%) and specificity was 99.3% (95% CI 98.7–99.6%) for trichomoniasis. Results from self-collected swabs were similar to clinician-collected swabs. CONCLUSION A molecular-based test using vaginal swabs collected by clinicians or patients can accurately diagnose most common bacterial, fungal, and protozoan causes of vaginitis. Women and their clinicians seeking accurate diagnosis and appropriate selection of efficacious treatment for symptoms of vaginitis might benefit from this molecular test.