MATERIALS AND METHODS: A review of multiple reports and kit inserts on the diagnostic performance of rapid tests from various manufacturers that are commercially available were performed. Only preliminary data are available currently.
RESULTS: From a total of nine rapid detection test (RDT) kits, three kits offer total antibody detection, while six kits offer combination SARS-CoV-2 IgM and IgG detection in two separate test lines. All kits are based on colloidal gold-labeled immunochromatography principle and one-step method with results obtained within 15 minutes, using whole blood, serum or plasma samples. The sensitivity for both IgM and IgG tests ranges between 72.7% and 100%, while specificity ranges between 98.7% to 100%. Two immunochromatography using nasopharyngeal or throat swab for detection of COVID-19 specific antigen are also reviewed.
CONCLUSIONS: There is much to determine regarding the value of serological testing in COVID-19 diagnosis and monitoring. More comprehensive evaluations of their performance are rapidly underway. The use of serology methods requires appropriate interpretations of the results and understanding the strengths and limitations of such tests.
METHODS: Samples were obtained from 172/192 children presenting to a site in rural India with acute encephalitis syndrome.
RESULTS: Using the reference VT ELISA, infection with Japanese encephalitis virus (JEV) was confirmed in 44 (26%) patients, with central nervous system infection confirmed in 27 of these; seven patients were dengue seropositive. Of the 121 remaining patients, 37 (31%) were JEV negative and 84 (69%) were JEV unknown because timing of the last sample tested was <10 day of illness or unknown. For patient classification with XCyton, using cerebrospinal fluid alone (the recommended sample), sensitivity was 77.8% (59.2-89.4) with specificity of 97.3% (90.6-99.2). For Panbio ELISA, using serum alone (the recommended sample), sensitivity was 72.5% (57.2-83.9) with specificity of 97.5% (92.8-99.1). Using all available samples for patient classification, sensitivity and specificity were 63.6% (95% CI: 48.9-76.2) and 98.4% (94.5-99.6), respectively, for XCyton ELISA and 75.0% (59.3-85.4) and 97.7% (93.3-99.2) for Panbio ELISA.
CONCLUSION: The two commercially available ELISAs had reasonable sensitivities and excellent specificities for diagnosing JEV.
METHODS: Ninety five first-time male attendees of the Genito-urinary Medicine Clinic in Hospital Kuala Lumpur were included in this cross-sectional study. The detection of C. trachomatis was achieved through direct fluorescence antibody (DFA) staining of urethral swabs and real-time polymerase chain reaction testing (Xpert® CT/NG assay) on urine specimens. N. gonorrhoeae was detected through Gram staining and culture of urethral swabs and Xpert® CT/ NG assay on urine specimens.
RESULTS: From the Xpert® CT/NG results, 11 (11.6%) attendees had chlamydia, 23 (24.2%) had gonorrhoea and 8 (8.4%) had both STIs. The sensitivity and specificity of DFA in detecting chlamydia compared to Xpert® CT/NG were 5.3% (95% CI: 0-28) and 94.7% (95% CI: 86-98), respectively. For gonorrhoea, the sensitivity and specificity of Gram staining were 90.3% (95% CI: 73-98) and 95.3% (86-99), respectively, whereas the sensitivity and specificity of culture compared to Xpert® CT/NG were 32.2% (95% CI: 17-51) and 100% (95% CI: 93-100), respectively.
CONCLUSION: Although Gram-stained urethral swab smears are sensitive enough to be retained as a screening tool for gonorrhoea, culture as well as DFA lack sensitivity and are poorly suited to screen for gonorrhoea and chlamydia, respectively. However, owing to their high specificity, conventional detection methods are still suitable as confirmatory tests for gonorrhoea and chlamydia.