Diagnostic performance of GenBody COVID-19 rapid antigen test for laboratory and non-laboratory medical professionals in real practice: A retrospective study

Point-of-care tests for coronavirus disease 2019 (COVID-19) antigen detection have been widely used for rapid diagnosis in various settings. However, research on the diagnostic performance of the COVID-19 antigen test performed by non-laboratory personnel is limited. In this study, we aimed to elucidate the diagnostic performance of GenBody COVID-19 rapid antigen between laboratory professionals and non-laboratory staff. We retrospectively analyzed the data of patients who underwent both GenBody COVID-19 rapid antigen testing and reverse transcription polymerase chain reaction (RT-PCR) between November 01, 2021, and June 30, 2022. The diagnostic performance of the antigen test was compared between laboratory and non-laboratory operators, using RT-PCR as the gold standard. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, positive predictive value, negative predictive value, and accuracy were calculated and sensitivity analysis was performed based on the PCR cycle threshold (Ct) value. Of the 11,963 patients, 1273 (10.6%) tested positive using real-time RT-PCR. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, positive predictive value, negative predictive value, and accuracy of the GenBody COVID-19 rapid antigen test with 95% confidence interval were 79.92% (77.26%-82.39%), 99.23% (98.73%-99.57%), 103.25 (62.31-171.11), 0.2 (0.18-0.23), 510.18 (299.81-868.18), 98.11% (96.91%-98.85%), 90.75% (89.64%-91.75%) and 92.76% (91.76%-93.67%), respectively, for non-laboratory staff and 79.80% (74.78%-84.22%), 99.99% (99.94%-100.00%), 6983.92 (983.03-49617.00), 0.2 (0.16-0.25), 34566.45 (4770.30-250474.46) 99.58% (97.09%-99.94%), 99.32% (99.15%-99.46%), and 99.33% (99.13%-99.48%), respectively, for laboratory staff. Notably, when the PCR Ct value exceeded 25, the sensitivity of both the groups decreased to < 40%. The diagnostic performance of GenBody COVID-19 rapid antigen performed by non-laboratory staff was comparable to that of laboratory professionals. However, it should be noted that the sensitivity of the antigen tests decreased when the PCR Ct value exceeded 25. Overall, the GenBody COVID-19 antigen test is a viable option for non-laboratory staff during an epidemic.

TB testing in HIV-positive patients prior to antiretroviral treatment

BACKGROUND: TB diagnosis in patients with HIV is challenging due to the lower sensitivities across tests. Molecular tests are preferred and the Xpert^® MTB/RIF assay has limitations in lower-income settings. We evaluated the performance of loop-mediated isothermal amplification (LAMP) and the lipoarabinomannan (LAM) test in HIV-positive, ART-naïve clinic patients.METHODS: A total of 783 eligible patients were enrolled; three spot sputum samples of 646 patients were tested using TB-LAMP, Xpert, smear microscopy and culture, while 649 patients had TB-LAM testing. Sensitivity, specificity, and negative and positive predictive values were estimated with 95% confidence intervals.RESULTS: Sensitivities for smear microscopy, TB-LAMP and Xpert were respectively 50%, 63% and 74% compared to culture, with specificities of respectively 99.2%, 98.5% and 97.5%. An additional eight were positive on TB-LAM alone. Seventy TB patients (9%) were detected using standard-of-care testing, an additional 27 (3%) were detected using study testing. Treatment was initiated in 57/70 (81%) clinic patients, but only in 56% (57/97) of all those with positive TB tests; 4/8 multidrug-resistant samples were detected using Xpert.CONCLUSION: TB diagnostics continue to miss cases in this high-burden setting. TB-LAMP was more sensitive than smear microscopy, and if followed by culture and drug susceptibility testing as required, can diagnose TB in HIV-positive patients. TB-LAM is a useful add-in test and both tests at the point-of-care would maximise yield.

A Comparative Assessment of the Nova Stat Profile Prime Plus® Critical Care Analyzer

BACKGROUND

Point-of-care testing (POCT) plays an integral role in the management of acutely ill patients presenting to the emergency department (ED). Due to its rapid turnaround time, POCT has been shown to improve ED workflow, reduce unnecessary admissions and lessen the burden on ED staff. The aim of the study was to compare the accuracy, precision and linearity of the Nova Stat Profile Prime Plus^® (Nova Biomedical, Waltham, MA, USA) to the Radiometer ABL800 FLEX^® (Radiometer South Africa Pty Ltd, Gauteng) and the Abbott i-stat Chem8+^® (Abbott, Princeton, NJ, USA) POCT analyzers.

METHODS

A convenience sample of 150 discarded whole blood specimens was obtained and analyzed. Paired test measurements were conducted for method comparison. Accuracy was measured by pairing individual results from the Nova Stat Profile Prime Plus^® with either the Radiometer ABL800 FLEX^® or the Abbot i-stat Chem8+^® analyzers by calculating the differences.

RESULTS

The with-in run percentage coefficient of variation (%CV) was below 2.4% for pH, carboxyhemoglobin (COHb), deoxyhemoglobin (HHb), total hemoglobin (tHb), total bilirubin (tBil), sodium (Na), potassium (K), chloride (Cl), ionized calcium (iCa), urea, glucose and lactate, and was below 5.1% for all other analytes. The day-to-day %CV was below 1.6% for pH, COHb, HHb, tHb, tBil, Na, K, Cl, iCa, urea, glucose and lactate, and below 6.10% for all other analytes. The correlation coefficient (r) was 0.351 and ranged from 0.897 to 0.998 for all analytes. The mean bias was minimal for all analytes.

CONCLUSION

There was a good correlation between the Nova Stat Profile Prime Plus^® and the Radiometer ABL800 FLEX^®/Abbott i-STAT Chem8+^® POCT analyzers. The Stat Profile Prime Plus^® exhibited good precision both within-run and day-to-day.

Application of UPT-POCT in Public Health Emergencies

Rapid and reliable detection of infectious agents on site is essential for timely initiation of medical treatment and post-exposure prophylactic measures when public health emergencies occur. However, the referee standard for confirmation of infectious agents remains laboratory diagnosis, which is time-consuming and not available in the field. UPT-POCT technology is a versatile tool that requires limited resources and can realize rapid detection of infectious agents on site, providing timely information for the quick response to public health emergencies.