RESUMO
Background: Cycle threshold (Ct) values from SARS-CoV-2 nucleic acid amplification tests have been used to estimate viral load for treatment decisions. Additionally, there is a need for high-throughput testing, consolidating a variety of assays on one random-access analyzer. Objectives: In this study, the clinical performance of the Alinity m SARS-CoV-2, RealTime SARS-CoV-2, and GeneXpert Xpress SARS-CoV-2/Flu/RSV assays was assessed. Methods: Alinity precision and detection rates were evaluated using a dilution series of the Alinity m SARS-CoV-2 positive control. In a retrospective study, 7 remnant external quality assessment (EQA) specimens and 200 remnant nasopharyngeal swab specimens (100 positive and 100 negative) were tested in the three assays. Results: Alinity had 100 % detection rate at 50 copies/mL and high reproducibility (Ct value coefficient of variation ≤3.1 %). All three assays correctly detected positive and negative EQA samples with comparable Ct values (max difference 2.38) and high linearity. In patient samples, positive percent agreement was 95 % (95 % CI 89-98 %) and negative percent agreement was 100 % (95 % CI 96-100 %) for Alinity, compared to the other two assays. Four specimens detected on Alinity m but not RealTime or Xpert had Ct values above 40. Assay results were highly correlated (r ≥ 0.94). Ct values (after addition of 10 unread cycles to the reported Ct of RealTime) were comparable across the three assays. Conclusions: Alinity m had high precision and accuracy and Ct values comparable to those of the RealTime and Xpert assays. The assays could be used interchangeably, with no need for adjustment of patient management decisions based on Ct values from each assay.
RESUMO
Objective of this study was to demonstrate the ubiquitous presence of glucose in urine of euglycemic cats by a highly sensitive glucose assay. The local electronic database was searched for results of quantitative urine glucose measurements in cats. A total of 325 feline urine glucose measurements were identified, of which 303 (93%) had been submitted by one of the co-authors working in a near-by small animal practice. After the exclusion of patients with kidney disease (n = 60), hyperthyroidism (n = 15), diabetes mellitus (n = 11), multiple diseases (n = 9) or steroid treatment (n = 3), as well as serial measurements (n = 87) and outliers (n = 8), the final study population consisted of 132 cats. Urine creatinine concentration was unavailable in five patients. Whereas all but one cat had glucose concentrations above the detection limit of the assay (0.11 mmol/L, Gluco-quant Enzyme Kit/Roche Diagnostics), no positive glucose dipstick test result (Combur 9-Test, Roche Diagnostics) was observed. The median (range) of urinary glucose concentration and the glucose-to-creatinine ratio (UGCR) was 0.389 (<0.11-1.665) mmol/L and 0.0258 (0.007-0.517) respectively. The UGCR was not affected by age, gender, breed or leukocyturia, whereas cats with hematuria had slightly higher values. Data show that so-called "basal glucosuria" is present in the majority of cats and by no means diagnostic for diabetes mellitus or renal glucosuria. This has to be considered when using bio-analytical methods with a low limit of quantification.