Evaluation of Serological SARS-CoV-2 Lateral Flow Assays for Rapid Point-of-Care Testing.

Rapid point-of-care tests (POCTs) for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies vary in performance. A critical need exists to perform head-to-head comparisons of these assays. The performances of 15 different lateral flow POCTs for the detection of SARS-CoV-2-specific antibodies were compared on a well-characterized set of 100 samples. Of these, 40 samples from known SARS-CoV-2-infected, convalescent individuals (collected an average of 45 days after symptom onset) were used to assess sensitivity. Sixty samples from the prepandemic era (negative control) that were known to represent infections with other respiratory viruses (rhinoviruses A, B, and C and/or coronavirus 229E, HKU1, and NL63 OC43) were used to assess specificity. The timing of seroconversion was assessed using five lateral flow assays (LFAs) and a panel of 272 longitudinal samples from 47 patients for whom the time since symptom onset was known. Among the assays that were evaluated, the sensitivity and specificity for any reactive band ranged from 55% to 97% and from 78% to 100%, respectively. Assessing the performance of the IgM and the IgG bands alone, sensitivity and specificity ranged from 0% to 88% and 80% to 100% for IgM and from 25% to 95% and 90% to 100% for IgG, respectively. Longitudinal testing revealed that the median times after symptom onset to a positive result were 7 days (interquartile range [IQR], 5.4 to 9.8) for IgM and 8.2 days (IQR, 6.3 to 11.3) for IgG. The testing performances differed widely among LFAs, with greatest amount of variation related to the sensitivity of the assays. The IgM band was the band most likely to misclassify prepandemic samples. The appearances of IgM and IgG bands occurred almost simultaneously.

Evaluation of Serological SARS-CoV-2 Lateral Flow Assays for Rapid Point of Care Testing.

BACKGROUND: Rapid point-of-care tests (POCTs) for SARS-CoV-2-specific antibodies vary in performance. A critical need exists to perform head-to-head comparison of these assays. METHODS: Performance of fifteen different lateral flow POCTs for the detection of SARS-CoV-2-specific antibodies was performed on a well characterized set of 100 samples. Of these, 40 samples from known SARS-CoV-2-infected, convalescent individuals (average of 45 days post symptom onset) were used to assess sensitivity. Sixty samples from the pre-pandemic era (negative control), that were known to have been infected with other respiratory viruses (rhinoviruses A, B, C and/or coronavirus 229E, HKU1, NL63 OC43) were used to assess specificity. The timing of seroconversion was assessed on five POCTs on a panel of 272 longitudinal samples from 47 patients of known time since symptom onset. RESULTS: For the assays that were evaluated, the sensitivity and specificity for any reactive band ranged from 55%-97% and 78%-100%, respectively. When assessing the performance of the IgM and the IgG bands alone, sensitivity and specificity ranged from 0%-88% and 80%-100% for IgM and 25%-95% and 90%-100% for IgG. Longitudinal testing revealed that median time post symptom onset to a positive result was 7 days (IQR 5.4, 9.8) for IgM and 8.2 days (IQR 6.3 to 11.3). CONCLUSION: The testing performance varied widely among POCTs with most variation related to the sensitivity of the assays. The IgM band was most likely to misclassify pre-pandemic samples. The appearance of IgM and IgG bands occurred almost simultaneously.

Evaluation of clinical performance of a novel urine-based HPV detection assay among women attending a colposcopy clinic.

BACKGROUND: Human papillomavirus (HPV) testing in urine offers a convenient approach for cervical cancer screening but has previously suffered from limited clinical sensitivity. OBJECTIVES: We evaluated clinical performance of the prototype Trovagene HPV test, a novel polymerase chain reaction assay that targets the E1 region of the HPV genome and detects and amplifies short fragments of cell-free HPV DNA in urine. STUDY DESIGN: We conducted a pilot study among 72 women referred to colposcopy following abnormal screening. Participants provided a urine sample prior to clinician-collected cervical sampling and colposcopically-directed punch biopsy. Trovagene HPV test results on urine samples were compared with cervical and urine testing by Linear Array HPV Genotyping Test (LA-HPV) for detection of histologically-confirmed cervical precancerous lesions. RESULTS: There was high concordance between urine samples tested by the Trovagene HPV test and corresponding cervical (87.5%) and urine (81.9%) samples tested by LA-HPV. The Trovagene HPV test had high sensitivity (92.3% for detecting CIN2/3, and 100% for CIN3), comparable to LA-HPV testing on cervical samples (96.0% and 100%, respectively), and higher than LA-HPV testing on urine samples (80.8% and 90.0%, respectively). In this referral population, the specificity of the Trovagene urine HPV test was non-significantly lower (29% for CIN2/3 and 25% for CIN3) than corresponding estimates of LA-HPV testing on cervical (36% and 28%, respectively) and urine (42% and 38%, respectively) samples. CONCLUSIONS: This pilot study suggests that the Trovagene HPV test has high sensitivity for urine-based detection of cervical precancer and merits evaluation in larger studies.

Comparison of human papillomavirus detections in urine, vulvar, and cervical samples from women attending a colposcopy clinic.

While urine-based sampling for human papillomavirus (HPV) is being explored as a simple and noninvasive approach for cervical cancer screening, data comparing HPV genotyping in urine and those in cellular sampling of the cervix and vulva, and their correlation with rigorously confirmed cervical disease status, are sparse. We performed HPV genotyping on voided-urine and clinician-collected vulvar and cervical samples from 72 women undergoing colposcopy. Although urine-based HPV carcinogenic HPV detection was lower (58.3%) than cervical (73.6%) and vulvar (72.1%) detection (P = 0.05 and 0.07, respectively), the agreement of urine HPV with cervical and vulvar HPV was moderate (kappa = 0.55) and substantial (kappa = 0.62), respectively. Urine-based carcinogenic HPV detection had a clinical sensitivity of 80.8% (95% confidence interval [CI] = 60.7 to 93.5) and a specificity of 53.3% (95% CI = 37.9 to 68.3) for diagnosing cervical intraepithelial neoplasia grades 2/3 (CIN2/3) on histology; 90.0% of CIN3 was positive for urine HPV. The corresponding sensitivity and specificity values for vulvar sampling were 92% (95% CI = 74 to 99) and 40.5% (95% CI = 25.6 to 56.7), and those for cervical sampling were 96.2% (95% CI = 80.4 to 99.9) and 40% (95% CI = 25.7 to 55.7), respectively. HPV16 was the most common carcinogenic genotype detectable in 25% of urine, 33.8% of vulvar, and 31.9% of cervical samples overall, with prevalence increasing with cervical disease grade, regardless of the sampling method. Stronger cervical HPV PCR signal strengths were associated with increased frequency of urine HPV detection. In summary, the relatively lower detection rates but comparable clinical performance of urine-based HPV sampling underscore the need for larger studies to evaluate urine-based sampling for cervical cancer screening, epidemiologic studies, and postvaccination HPV disease surveillance.

Agreement for HPV genotyping detection between self-collected specimens on a FTA cartridge and clinician-collected specimens.

The current method of transporting self-collected cervicovaginal specimen for HPV DNA testing relies on liquid based medium, which is challenging and expensive to transport. A novel, dry storage and transportation device, Whatman indicating FTA™ Elute Cartridge, avoids some of the pitfalls of liquid-based medium. This method has been shown to be comparable to liquid-based collection medium, but relative performance of self-collected (SC) and clinician-collected (CC) samples onto FTA cards has not been reported. The objective of this study is to compare the analytic performance of self- and clinician-collected samples onto FTA cartridges for the detection of carcinogenic HPV using Linear Array. There was a 91% agreement, 69% positive agreement, and kappa of 0.75 between the clinician-collected and self-collected specimens for detection of any carcinogenic HPV genotype. When the HPV results were categorized hierarchically according to cervical cancer risk, there was no difference in the distribution of the HPV results for the clinician- and self-collected specimens (p=0.7). This study concludes that FTA elute cartridge is a promising method of specimen transport for cervical cancer screening programs considering using self-collected specimen and HPV testing. Larger studies with clinical endpoints are now needed to assess the clinical performance.