Comparative evaluation of Panbio and SD Biosensor antigen rapid diagnostic tests for COVID-19 diagnosis.

The aim of our study was to evaluate the diagnostic performance of two antigen rapid diagnostic tests (Ag-RDTs) to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We evaluated Panbio and SD-Biosensor Ag-RDTs. We employed 186 polymerase chain reaction (PCR) negative samples to evaluate the specificity and 170 PCR positive samples to assess the sensitivity. We evaluated their sensitivity according to Cycle threshold (C t ) values and days post onset of symptoms (d.p.o.). Tests were compared using the McNemar's test. Agreement was evaluated using the kappa score. Specificity was 100% for Panbio and 97.3% for SD-Biosensor. Sensitivity for samples with C t ≤ 20 was 100% for both assays and for samples with C t = 20-25 was 93.0% (Panbio) and 95.3% (SD-Biosensor) (p = 1.000). Sensitivity decreased for samples wit C t = 25-30 (Panbio: 41.3%, SD-Biosensor: 52.2%, p = 0.125) and samples with C t ≥ 30 (Panbio: 5.0%, SD-Biosensor: 17.5%, p = 0.063). Sensitivity within seven d.p.o. was 87.7% for Panbio and 90.4% for SD-Biosensor and notably decreased after seven d.p.o. Agreement with PCR was excellent for high viral load samples (C t ≤ 25): Panbio, 98.9%, kappa = 0.974; SD-Biosensor, 97.4%, kappa = 0.940. Agreement between Ag-RDTs was excellent (94.9%, kappa = 0.882). Panbio and SD-Biosensor Ag-RDTs showed excellent agreement and diagnostic performance results for samples with high viral loads (C t ≤ 25) or samples within seven d.p.o.

Diagnostic performance of CerTest and Panbio antigen rapid diagnostic tests to diagnose SARS-CoV-2 infection.

OBJECTIVES: Antigen rapid diagnostic tests (Ag-RDT) have been developed as reliable tools to control the SARS-CoV-2 pandemic. The objective of our study was to evaluate the diagnostic performance of two Ag-RDTs. METHODS: We evaluated CerTest SARS-CoV-2 Ag One Step Card Test and Panbio COVID-19 Ag Rapid Test Device Ag-RDTs. We included 320 nasopharyngeal samples: 150 PCR negative samples to assess the specificity and 170 PCR positive samples to evaluate the sensitivity. We also evaluated their sensitivity according to cycle threshold (Ct) values and the time from the onset of symptoms. Tests were compared using the McNemar's test and agreement was evaluated using the kappa score (k). RESULTS: Both Ag-RDTs showed a specificity of 100 %. Overall sensitivity was 53.5 % for CerTest and 60.0 % for Panbio. For samples with Ct≤ 25, sensitivity was 94.0 % for CerTest and 96.4 % for Panbio (p = 0.500). Regarding samples with Ct>25, sensitivity was 14.0 % for CerTest and 24.4 % for Panbio (p = 0.004). Sensitivity for samples within the first 5 days after the onset of symptoms were 84.8 % for CerTest and 91.3 % for Panbio (p = 0.250) and notably decreased for samples taken after the fifth day. Both Ag-RDTs showed an excellent agreement between them (agreement = 96.7 %, k = 0.920). Agreement with PCR was also excellent for high viral load samples (Ct<25) for CerTest (98.0 %, k = 0.954) and Panbio (98.8 %, k = 0.973). CONCLUSIONS: CerTest SARS-CoV-2 and Panbio COVID-19 Ag showed excellent performance and agreement results for samples with high viral loads (Ct ≤ 25) or samples taken within the first 5 days after the onset of symptoms.

Influence of intravenous thiamine supplementation on blood lactate concentration prior to cardiac surgery: A double-blinded, randomised controlled pilot study.

BACKGROUND: Stress related to surgery and critical illness depletes thiamine, essential in energy metabolism, and might result in high blood lactate concentrations and higher mortality. OBJECTIVES: We hypothesised that thiamine supplementation would increase blood concentration of thiamine and reduce blood lactate concentration postoperatively. Moreover, we aimed to identify the prevalence of, and risk factors for, high blood lactate concentrations. DESIGN: This was a double-blind, randomised controlled pilot study from February to July 2012 including 30 patients scheduled for cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Patients were assigned randomly to receive thiamine (300 mg in 0.9% Normal saline solution) or placebo (0.9% Normal saline) preoperatively. MAIN OUTCOME MEASURES: One arterial blood sample was taken preoperatively and another postoperatively to measure thiamine concentration, and multiple samples were taken during surgery and ICU stay to determine lactate concentrations. Twenty-four hour urine samples were collected to measure urinary thiamine concentration. Preoperatively, we assessed extracellular mass to body cell mass ratio (ECM/BCM). RESULTS: The mean (SD) age of the patients was 58 (12) years, 73% were overweight, 10% were malnourished and the prevalence of thiamine deficiency was 10%. Patients in the thiamine group had significantly higher blood thiamine concentrations 2 days postoperatively [805.2 ± 289.8 ng g(-1) haemoglobin (Hb)] than those in the placebo group (591.2 ± 100.7 ng g(-1) Hb, P < 0.01). The mean blood lactate concentration changed significantly over time, but did not differ significantly between the groups. Patients with ECM/BCM more than 1 had higher lactate concentrations on admission to ICU than those with ECM/BCM less than 1 (2.1 ± 0.7 vs. 1.7 ± 0.6, P = 0.09) and were at a significantly greater risk of having a higher lactate concentration on ICU admission [odds ratio (OR) 13.5, 95% confidence interval (95% CI) 1.0 to 179.4, P < 0.05]. On the basis of these results, a sample size calculation for a larger study has been facilitated. CONCLUSION: Thiamine supplementation caused normalisation of blood and urine concentrations postoperatively but without a significant reduction in lactate concentration or clinical outcome. Body composition played an important role in lactate formation. Further research focusing on preoperative screening and optimal treatment of high lactate concentrations in this specific population is warranted. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT01524315.