Diagnostic accuracy of the Biosynex CryptoPS cryptococcal antigen semi-quantitative lateral flow assay in patients with advanced HIV disease.

Background: High cryptococcal antigen (CrAg) titers in blood are associated with subclinical meningitis and mortality in CrAg-positive individuals with advanced HIV-disease (AHD). We evaluated a novel semi-quantitative lateral flow assay (LFA), CryptoPS, that may be able to identify individuals with high CrAg titers in a cohort of AHD patients undergoing CrAg screening.Methods: In a prospective cohort of patients with AHD (CD4 ≤200 cells/μL) receiving CD4 count testing, CryptoPS and IMMY LFA CrAg testing were performed on whole blood by two operators blinded to results of the other assay. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CryptoPS were assessed against IMMY LFA as a reference. CryptoPS low-titer (T1 band) and high-titer (T2 band) results were compared against IMMY LFA titers obtained through serial dilution.Results: 916 specimens were tested. Sensitivity of the CryptoPS assay was 61.0% (25/41, 95% confidence interval [95%CI]: 44.5-75.8), specificity 96.6% (845/875, 95%CI: 95.1-97.7), PPV 45.5% (95%CI: 32.0-59.4), and NPV 98.1% (95%CI: 97.0-98.9). All (16/16) CryptoPS false-negatives were samples with IMMY titers ≤1:160. Of 29 patients (30 specimens) who tested positive on CryptoPS but negative on IMMY LFA, none developed cryptococcal meningitis over 3-months follow-up without fluconazole. Median CrAg titers were 1:20 (interquartile range [IQR] 0-1:160) in CryptoPS T1-positive samples and 1:2560 (IQR 1:1280-1:10240) in T2-positives.Conclusions: Diagnostic accuracy of the CryptoPS assay was sub-optimal in the context of CrAg screening, with poor sensitivity at low CrAg titers. However, the CryptoPS assay reliably detected individuals with high titers associated with poor outcomes

Trichomonas vaginalis: Clinical relevance, pathogenicity and diagnosis

Trichomonas vaginalis is the etiological agent of trichomoniasis, the most prevalent non-viral sexually transmitted disease worldwide. Trichomoniasis is a widespread, global health concern and occurring at an increasing rate. Infections of the female genital tract can cause a range of symptoms, including vaginitis and cervicitis, while infections in males are generally asymptomatic. The relatively mild symptoms, and lack of evidence for any serious sequelae, have historically led to this disease being under diagnosed, and under researched. However, growing evidence that T. vaginalis infection is associated with other disease states with high morbidity in both men and women has increased the efforts to diagnose and treat patients harboring this parasite. The pathology of trichomoniasis results from damage to the host epithelia, caused by a variety of processes during infection and recent work has highlighted the complex interactions between the parasite and host, commensal microbiome and accompanying symbionts. The commercial release of a number of nucleic acid amplification tests (NAATs) has added to the available diagnostic options. Immunoassay based Point of Care testing is currently available, and a recent initial evaluation of a NAAT Point of Care system has given promising results, which would enable testing and treatment in a single visit

Association of semi-quantitative cryptococcal antigen results in plasma with subclinical cryptococcal meningitis and mortality among patients with advanced HIV disease.

Blood cryptococcal antigen (CrAg) titers >160 are associated with concurrent subclinical cryptococcal meningitis (CM). When lumbar puncture (LP) is not immediately available in a CrAg screening program, semi-quantitative CrAg assays may provide risk stratification for CM. Two semi-quantitative assays (SQ [Immuno-Mycologics, Norman, OK, USA] and CryptoPS [Biosynex, Strasbourg, France]) were evaluated against a qualitative lateral flow assay (LFA) using 194 plasma samples from a cohort of HIV-seropositive individuals with CD4 counts 160. Fifty individuals with antigenemia had an LP; a clinically useful SQ score that identified all ten cases of subclinical CM was ≥3 (100% sensitivity, 55% specificity). Patients with an SQ score of 3 or 4 also had a 2.2-fold increased adjusted hazards of 6-month mortality (95% CI: 0.79-6.34; p = 0.13) versus those with score of <3. Nine of ten patients with subclinical CM had a strong-positive CryptoPS result versus 10/40 without subclinical CM (p < 0.001). Semi-quantitative assays offered a sensitive though not specific means of gauging the risk of concurrent CM in this patient population. LAY SUMMARY: We evaluated two single-step laboratory tests that can quantify the amount of cryptococcal antigen in plasma of patients with advanced HIV disease and could thus gauge the risk of concurrent cryptococcal meningitis and subsequent mortality. These tests are not a substitute for a lumbar puncture