The Panbio COVID-19 Ag Rapid Test Device (Panbio COVID-19 Ag, Abbott Rapid Diagnostics) is a lateral flow immunochromatographic assay targeting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleoprotein in nasopharyngeal specimens for the diagnosis of coronavirus disease 2019 (COVID-19). This study aimed to verify the performance of the Panbio COVID-19 Ag for implementation in clinical laboratories.
Sixty nasopharyngeal swab specimens (30 positive and 30 negative) dipped in transport medium, and COVID-19 was confirmed using real-time RT-PCR using Allplex SARS-CoV-2 assay (Seegene), were tested using the Panbio COVID-19 Ag. Reproducibility was evaluated using positive and negative control materials. Sensitivity and specificity were calculated based on the results of real-time RT-PCR as the standard test method.
Reproducibility was confirmed by the consistent results of repeated tests of the quality control materials. The overall sensitivity and specificity of Panbio COVID-19 Ag were 50.0% and 100.0%, respectively. Panbio COVID-19 Ag demonstrated high sensitivity (88.2%) in analyzing the detection limit cycle threshold (Ct) value of 26.67 provided by the manufacturer as a positive criterion, and the sensitivity was 100.0% for the positive criterion of Ct values <25, although it was less sensitive for Ct ≥25.
Considering the high sensitivity for positive samples with Ct values <25 and the rapid turnaround of results, Panbio COVID-19 Ag can be used in clinical laboratories to diagnose COVID-19 in limited settings.
Six sigma is a quality management system for the assessment of precision and accuracy. We aim to apply the six sigma rule to quality control (QC) of point-of-care (POC) glucose meters in a tertiary hospital.
Thirty POC glucose meters installed at Ewha Womans University Mokdong Hospital were monitored between January 2013 and March 2014. The QC data from the POC glucose meters at low and high levels were collected. The monthly mean, standard deviation, bias, coefficient of variation, and mean sigma metrics were calculated. The correlation between accuracy and precision was assessed based on the percentage bias and coefficient of variation. Comprehensive instructions on the QC and maintenance of the devices were provided in the departments with poor sigma scores. A follow-up assessment was performed after the intervention.
The mean sigma values for the low and high controls were 3.29 and 3.71, respectively. At the low and high controls, 36.6% and 10% of the glucose meters showed a sigma value <3. The causes of low sigma values included the use of expired control materials, prolonged air exposure of the sample strip, lack of user training, and errors in device maintenance. On follow-up monitoring for 3 months following QC intervention, 23.3% (low control) and 6.6% (high control) of the glucose meters scored a sigma value <3, indicating improved QC.
Sigma metrics-based QC can successfully improve accuracy and precision of POC glucose meters in an objective and quantitative manner and can be used for follow up after QC intervention.
Citations
The Xpert Carba-R Assay is a diagnostic test designed for the rapid detection and differentiation of the
The analytical limit of detection was determined with two suspensions of carbapenemase-producing
In bacterial isolates, concordant results between the Xpert Carba-R Assay and PCR were found in 20 of 21; 8 KPC, 8 NDM, 1 IMP, and 2 multiple carbapenamase genes (KPC/NDM, NDM/OXA) were detected both by Xpert Carba-R Assay and PCR. In one GES-positive isolate, Xpert Carba-R Assay showed a negative result as expected. One VIM-positive isolate tested negative by Xpert Carba-R Assay. Complete concordance was seen in rectal swab specimens: 4 specimens with KPC and 17 specimens with negative results both by Xpert Carba-R Assay and surveillance culture. Among the 10 contrived stool specimens, Xpert Carba-R Assay detected carbapenemase genes in 9 specimens as expected according to the CPE strains spiked into the contrived stool; 2 KPC, 4 NDM, 1 IMP, and 2 multiple carabapenamase genes (NDM/KPC, NDM/OXA). One VIM-positive specimen tested negative by Xpert Carba-R Assay.
In conclusion, the Xpert Carba-R Assay can be used to identify carbapenemase gene in bacterial isolates cultured from clinical specimens and detect CPE carrier using rectal swab in clinical laboratories.