Evaluation of the INDICAID COVID-19 Rapid Antigen Test in Symptomatic Populations and Asymptomatic Community Testing.

As the COVID-19 pandemic progresses, there is an increasing need for rapid, accessible assays for SARS-CoV-2 detection. We present a clinical evaluation and real-world implementation of the INDICAID COVID-19 rapid antigen test (INDICAID rapid test). A multisite clinical evaluation of the INDICAID rapid test using prospectively collected nasal (bilateral anterior) swab samples from symptomatic subjects was performed. The INDICAID rapid test demonstrated a positive percent agreement (PPA) and negative percent agreement (NPA) of 85.3% (95% confidence interval [95% CI], 75.6% to 91.6%) and 94.9% (95% CI, 91.6% to 96.9%), respectively, compared to laboratory-based reverse transcriptase PCR (RT-PCR) using nasal specimens. The INDICAID rapid test was then implemented at COVID-19 outbreak screening centers in Hong Kong as part of a testing algorithm (termed "dual-track") to screen asymptomatic individuals for prioritization for confirmatory RT-PCR testing. In one approach, preliminary positive INDICAID rapid test results triggered expedited processing for laboratory-based RT-PCR, reducing the average time to confirmatory result from 10.85 h to 7.0 h. In a second approach, preliminary positive results triggered subsequent testing with an onsite rapid RT-PCR, reducing the average time to confirmatory result to 0.84 h. In 22,994 asymptomatic patients, the INDICAID rapid test demonstrated a PPA of 84.2% (95% CI, 69.6% to 92.6%) and an NPA of 99.9% (95% CI, 99.9% to 100%) compared to laboratory-based RT-PCR using combined nasal/oropharyngeal specimens. The INDICAID rapid test has excellent performance compared to laboratory-based RT-PCR testing and, when used in tandem with RT-PCR, reduces the time to confirmatory positive result. IMPORTANCE Laboratory-based RT-PCR, the current gold standard for COVID-19 testing, can require a turnaround time of 24 to 48 h from sample collection to result. The delayed time to result limits the effectiveness of centralized RT-PCR testing to reduce transmission and stem potential outbreaks. To address this, we conducted a thorough evaluation of the INDICAID COVID-19 rapid antigen test, a 20-minute rapid antigen test, in both symptomatic and asymptomatic populations. The INDICAID rapid test demonstrated high sensitivity and specificity with RT-PCR as the comparator method. A dual-track testing algorithm was also evaluated utilizing the INDICAID rapid test to screen for preliminary positive patients, whose samples were then prioritized for RT-PCR testing. The dual-track method demonstrated significant improvements in expediting the reporting of positive RT-PCR test results compared to standard RT-PCR testing without prioritization, offering an improved strategy for community testing and controlling SARS-CoV-2 outbreaks.

A 3-year, prospective, randomized, controlled study on amino acid dialysate in patients on CAPD.

BACKGROUND: Malnutrition is prevalent in patients on continuous ambulatory peritoneal dialysis (CAPD) and confers a poor prognosis. Inadequate nutrient intake is an important contributing factor. Although short-term studies have shown mild to modest nutritional benefit with amino acid dialysate, its long-term effects and tolerability remain obscure. METHODS: The authors have performed a 3-year, randomized, prospective, controlled study of amino acid dialysate in malnourished Chinese patients on CAPD. Sixty patients were assigned randomly to either replace 1 exchange daily with amino acid dialysate (Nutrineal; DAA group, n = 30) or to continue with dextrose dialysate (Dianeal; DD group, n = 30). RESULTS: The 2 groups had similar mortality, hospitalization duration, serial C-reactive protein levels, and drop-out rates during the study. Biochemical nutritional parameters including albumin and cholesterol decreased in the DD group but remained stable or increased in the DAA group. The composite nutritional index did not differ between the 2 groups throughout the study period. Triglyceride decreased only in DAA-treated patients. Normalized protein equivalent of nitrogen appearance and dietary protein intake showed a sustained increase only in DAA patients. The nutritional benefit of DAA appeared more prominent in women, whose lean body mass and body mass index was maintained with DAA but not with DD. Mass transfer area coefficient for creatinine increased in DAA-treated patients, whereas that for urea as well as macromolecular restriction coefficients remained stable. Total Kt/V(urea) and daily ultrafiltration volume were similarly maintained in the 2 groups throughout the study. CONCLUSION: Long-term administration of amino acid dialysate is well tolerated and presents a means to improve the nutritional status in high-risk patients. The current study, however, has not shown a significant effect of amino acid dialysate on patient survival.

Significance of monocytic cytokines at single cell level for the immune responsiveness in renal transplant recipients.

Cytokine dysregulation is an important factor underlying the immune unresponsiveness to hepatitis B vaccination (HBV) in renal transplant recipients. This study investigated the relationship between monocyte-derived interleukin-6 (IL-6) and interleukin-10 (IL-10) production and the immune responsiveness using flow cytometry (cytoflow) after whole blood culture. According to their previous response to hepatitis B vaccination, 40 renal transplant recipients were divided into two groups of 20 patients. The percentage of CD 14+ monocytes stained positive for intracellular IL-6 or IL-10 was measured using flow cytometry after 4 and 20 h of whole blood culture with lipopolysaccharide stimulation. The percentage of CD 14+/IL-6+ cells after incubation in vitro for 4 h was lower in the responders compared to the non-responders and controls (27.15+/-8.93 vs 35.47+/-9.95, P=NS; and 37.06+/-10.89, P<0.05 respectively). The staining intensity of IL-6 at 4 h for responders was also significantly reduced. At 20 h, there were a significantly higher percentage of CD 14+/IL-10+ positive cells in the responders compared to the non-responders (41.87+/-18.39 vs 27.55+/-17.25, P<0.05). These results indicate that alteration of intracellular cytokine profile in activated monocytes distinguishes the HBV vaccination responders from the non-responders among renal transplant recipients. The capacity to upregulate monocyte IL-10 production in this subset of patients may modulate the immune responsiveness and effectively assists in mounting a positive response to HBV vaccination.

Cystatin C assay for the detection of renal dysfunction in Chinese renal transplant recipients.

BACKGROUND: Accurate and rapid assessment of kidney function in patients after renal transplantation is of major significance. We investigated whether cystatin C can accurately reflect creatinine clearance over the entire range of kidney graft function. The performance of serum cystatin C as a screening marker of reduced creatinine clearance in renal transplantation was evaluated and compared to serum creatinine. METHODS: Serum cystatin C, serum creatinine and creatinine clearance were measured in 103 adult renal transplant recipients. The cystatin C assay was performed using particle-enhanced immunonephelometry. RESULTS: We demonstrated a significant linear correlation between 1/cystatin C and creatinine clearance over the entire range of transplant function, comparable to that of creatinine. Cystatin C detected reduced creatinine clearance with higher sensitivity of 92.9% (95% CI 80.5-98.4%) than serum creatinine, 71.4% (95% CI 55.4-84.3%). From the receiver operating characteristic (ROC) plots, serum cystatin C is superior to serum creatinine at 90% and 95% sensitivity. CONCLUSIONS: Serum cystatin C accurately reflects creatinine clearance over the entire range of transplant kidney function and is more efficacious than serum creatinine to detect reduced creatinine clearance in renal transplant recipients.

Prevalence and significance of hepatitis GB virus-c/hepatitis G virus viremia in a large cohort of patients with chronic hepatitis B infection, with chronic hepatitis C infection, and on renal replacement therapy in Hong Kong.

A total of 455 patients were recruited to study the prevalence of hepatitis GB virus-C/hepatitis G virus viremia in Hong Kong. There was no significant increase in the prevalence of hepatitis GB virus-C viremia in asymptomatic hepatitis B virus- and hepatitis C virus-infected patients compared to that of controls (1.56% and 7.14%, respectively, vs 3.85%, both P = NS). Renal patients as a whole had a significantly higher prevalence of hepatitis GB virus-C viremia compared to that of controls (13.95% vs 3.85%, P = 0.0271). The duration of the replacement therapy, especially for patients with peritoneal dialysis was associated with a higher chance of hepatitis GB virus-C viremia. Among renal patients, renal transplanted patients had the highest prevalence of hepatitis GB virus-C viraemia (19.1%) probably because of a higher susceptibility as a result of immunosuppression. However, hepatitis GB virus-C viraemia did not cause liver biochemistry derangement in renal transplanted patients.