Cervical specimen order and performance measures of Chlamydia trachomatis diagnostic testing

Performance evaluation and acceptability of point-of-care Trichomonas vaginalis testing in adult female emergency department patients

We evaluated the accuracy and perception of a patient self-administered, tablet-facilitated rapid Trichomonas vaginalis (TV) point-of-care (POC) test in adult female emergency department (ED) patients.ED patients undergoing gynecologic examination were eligible. Each consented participant self-collected a vaginal swab, performed a tablet-facilitated TV rapid test using the OSOM® Trichomonas Rapid Test, and completed pre- and post-test self-surveys. After the self-test, the clinician collected one standard-of-care (SOC) vaginal swab for wet-mount testing and two for research. The research coordinator performed the TV rapid test using the clinician-collected swab, and reported the results to the clinician and patient. If the self- and coordinator-performed results were discordant, a TV nucleic acid amplification test (NAAT) was performed in a clinical laboratory. A survey was later administered to providers to assess their perceptions of the utility of the POC TV test.Of the 136 participants, 134 (98.5%) completed self-testing; two had invalid results. Comparing coordinator-performed TV rapid test adjudicated with NAAT, the sensitivity and specificity of self-administered test was 96.0% and 100%, respectively. The wet mount had a sensitivity of 52.0% and specificity of 100%. TV detection increased from 9.6% with wet mount to 18.4% with the TV rapid test. Most women (82.0%) stated self-testing was "not at all hard" (versus 66.2% before testing, p < 0.001). Clinicians indicated the TV rapid test affected their clinical management in 48.5% of cases, including 82.6% of positive cases and 41.6% of negative cases.ED patients were able to reliably collect, perform, and interpret their own POC TV test using tablet instructions. Both participants and providers reported high levels of acceptability of POC TV testing, which nearly doubled rates of TV detection.

Performance of swabs, lavage, and diluents to quantify biomarkers of female genital tract soluble mucosal mediators

Background

Measurement of immune mediators and antimicrobial activity in female genital tract secretions may provide biomarkers predictive of risk for HIV-1 acquisition and surrogate markers of microbicide safety. However, optimal methods for sample collection do not exist. This study compared collection methods.

Methods

Secretions were collected from 48 women (24 with bacterial vaginosis [BV]) using vaginal and endocervical Dacron and flocked swabs. Cervicovaginal lavage (CVL) was collected with 10 mL of Normosol-R (n = 20), saline (n = 14), or water (n = 14). The concentration of gluconate in Normosol-R CVL was determined to estimate the dilution factor. Cytokine and antimicrobial mediators were measured by Luminex or ELISA and corrected for protein content. Endogenous anti-HIV-1 and anti-E. coli activity were measured by TZM-bl assay or E. coli growth.

Results

Higher concentrations of protein were recovered by CVL, despite a 10-fold dilution of secretions, as compared to swab eluents. After protein correction, endocervical swabs recovered the highest mediator levels regardless of BV status. Endocervical and vaginal flocked swabs recovered significantly higher levels of anti-HIV-1 and anti-E. coli activity than Dacron swabs (P<0.001). BV had a significant effect on CVL mediator recovery. Normosol-R tended to recover higher levels of most mediators among women with BV, whereas saline or water tended to recover higher levels among women without BV. Saline recovered the highest levels of anti-HIV-1 activity regardless of BV status.

Conclusions

Endocervical swabs and CVL collected with saline provide the best recovery of most mediators and would be the optimal sampling method(s) for clinical trials.

APTIMA assay on SurePath liquid-based cervical samples compared to endocervical swab samples facilitated by a real time database

Background:

Liquid-based cytology (LBC) cervical samples are increasingly being used to test for pathogens, including: HPV, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) using nucleic acid amplification tests. Several reports have shown the accuracy of such testing on ThinPrep (TP) LBC samples. Fewer studies have evaluated SurePath (SP) LBC samples, which utilize a different specimen preservative. This study was undertaken to assess the performance of the Aptima Combo 2 Assay (AC2) for CT and GC on SP versus endocervical swab samples in our laboratory.

Materials and Methods:

The live pathology database of Montefiore Medical Center was searched for patients with AC2 endocervical swab specimens and SP Paps taken the same day. SP samples from CT-and/or GC-positive endocervical swab patients and randomly selected negative patients were studied. In each case, 1.5 ml of the residual SP vial sample, which was in SP preservative and stored at room temperature, was transferred within seven days of collection to APTIMA specimen transfer tubes without any sample or patient identifiers. Blind testing with the AC2 assay was performed on the Tigris DTS System (Gen-probe, San Diego, CA). Finalized SP results were compared with the previously reported endocervical swab results for the entire group and separately for patients 25 years and younger and patients over 25 years.

Results:

SP specimens from 300 patients were tested. This included 181 swab CT-positive, 12 swab GC-positive, 7 CT and GC positive and 100 randomly selected swab CT and GC negative patients. Using the endocervical swab results as the patient’s infection status, AC2 assay of the SP samples showed: CT sensitivity 89.3%, CT specificity 100.0%; GC sensitivity and specificity 100.0%. CT sensitivity for patients 25 years or younger was 93.1%, versus 80.7% for patients over 25 years, a statistically significant difference (P = 0.02).

Conclusions:

Our results show that AC2 assay of 1.5 ml SP samples transferred to APTIMA specimen transfer medium within seven days is sufficiently sensitive and specific to be used to screen for CT and GC. CT sensitivity may be somewhat reduced in samples from patients over 25 years. SP specimens retained in the original SP fixative for longer time intervals also may have decreased sensitivity, due to deterioration of RNA, but this was not assessed in this study. The ability to tap the live pathology database is a valuable tool that can useful to conduct clinical studies without a costly prospective clinical trial.