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.

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.

Association between cigarette smoking and mutation of the p53 gene in squamous-cell carcinoma of the head and neck

BACKGROUND

Although epidemiologic studies have long associated tobacco and alcohol use with the development of squamous-cell carcinoma of the head and neck, the molecular targets of these carcinogens have yet to be identified. We performed a molecular analysis to determine the pattern of mutations in the p53 gene in neoplasms from patients with squamous-cell carcinoma of the head and neck and a history of tobacco or alcohol use.

METHODS

Sequence analysis of the conserved regions of the p53 gene was performed in tumor samples from 129 patients with primary squamous-cell carcinoma of the head and neck. We then used statistical analysis to identify any patient characteristics associated with mutation of the p53 gene.

RESULTS

We found p53 mutations in 42 percent of the patients (54 of 129). Fifty-eight percent of the patients who smoked cigarettes and used alcohol (37 of 64; 95 percent confidence interval, 45 to 70 percent), 33 percent of the patients who smoked but abstained from alcohol (13 of 39; 95 percent confidence interval, 19 to 50 percent), and 17 percent of the patients who neither smoked nor drank alcohol (4 of 24, 95 percent confidence interval, 5 to 37 percent) had p53 mutations (P = 0.001). (Two patients used alcohol but did not smoke, and neither had a p53 mutation.) Furthermore, 100 percent of the mutations in the patients who neither drank nor smoked occurred at sites containing cytidine phosphate guanosine dinucleotides (potentially representing endogenous mutations) within the p53 gene (5 of 5 mutations; 95 percent confidence interval, 48 to 100 percent), whereas only 23 percent of those in cigarette smokers consisted of such changes (12 of 53 mutations; 95 percent confidence interval, 12 to 36 percent; P = 0.001).

CONCLUSIONS

In our study, a history of tobacco and alcohol use was associated with a high frequency of p53 mutations in patients with squamous-cell carcinoma of the head and neck. Preliminary evidence linked cigarette smoking to p53 mutations at nonendogenous mutation sites. Our findings suggest a role for tobacco in the molecular progression of squamous-cell carcinoma of the head and neck and support the epidemiologic evidence that abstinence from smoking is important to prevent head and neck cancer.

Molecular assessment of histopathological staging in squamous-cell carcinoma of the head and neck

BACKGROUND

Surgical oncologists rely heavily on the histopathological assessment of surgical margins to ensure total excision of the tumor in patients with head and neck cancer. However, current techniques may not detect small numbers of cancer cells at the margins of resection or in cervical lymph nodes.

METHODS

We used molecular techniques to determine whether clonal populations of infiltrating tumor cells harboring mutations of the p53 gene could be detected in histopathologically negative surgical margins and cervical lymph nodes of patients with squamous-cell carcinoma of the head and neck.

RESULTS

We identified 25 patients with primary squamous-cell carcinoma of the head and neck containing a p53 mutation who appeared to have had complete tumor resection on the basis of a negative histopathological assessment. In 13 of these 25 patients, molecular analysis was positive for a p53 mutation in at least one tumor margin. In 5 of 13 patients with positive margins by this method (38 percent), the carcinoma has recurred locally, as compared with none of 12 patients with negative margins (P = 0.02 by the log-rank test). Furthermore, molecular analysis identified neoplastic cells in 6 of 28 lymph nodes (21 percent) that were initially negative by histopathological assessment.

CONCLUSIONS

Among specimens initially believed to be negative by light microscopy, a substantial percentage of the surgical margins and lymph nodes from patients with squamous-cell carcinoma of the head and neck contained p53 mutations specific for the primary tumor. Patients with these positive margins appear to have a substantially increased risk of local recurrence. Molecular analysis of surgical margins and lymph nodes can augment standard histopathological assessment and may improve the prediction of local tumor recurrence.

The incidence of p53 mutations increases with progression of head and neck cancer

To establish a genetic model of the progression of head and neck squamous carcinoma we have defined the incidence and timing of p53 mutations in this type of cancer. We sequenced the conserved regions of the p53 gene in 102 head and neck squamous carcinoma lesions. These included 65 primary invasive carcinomas and 37 noninvasive archival specimens consisting of 13 severe dysplasias and 24 carcinoma in situ lesions. The incidence of p53 mutations in noninvasive lesions was 19% (7/37) and increased to 43% (28/65) in invasive carcinomas. These data suggest that p53 mutations can precede invasion in primary head and neck cancer. Furthermore, the spectrum of codon hotspots is similar to that seen in squamous carcinoma of the lung and 64% of mutations are at G nucleotides, implicating carcinogens from tobacco smoke in the etiology of head and neck squamous carcinoma.