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

Area of Science:

• Clinical diagnostics
• Microbiology
• Gynecologic pathology

Background:

• Liquid-based cytology (LBC) is increasingly used for pathogen detection, including Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC).
• While ThinPrep (TP) LBC accuracy is documented, fewer studies evaluate SurePath (SP) LBC, which uses a different preservative.
• This study assessed the performance of the Aptima Combo 2 Assay (AC2) for CT and GC on SP samples.

Purpose of the Study:

• To evaluate the diagnostic performance of the Aptima Combo 2 Assay (AC2) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC).
• To compare the accuracy of AC2 testing on SurePath (SP) liquid-based cytology samples versus traditional endocervical swab samples.

Main Methods:

• Retrospective analysis of 300 patients' SurePath (SP) samples and corresponding endocervical swab results from Montefiore Medical Center.
• Residual SP samples were transferred to APTIMA specimen transfer tubes within seven days and tested using the AC2 assay on the Tigris DTS System.
• Results were compared between SP samples and endocervical swabs, stratified by age (≤25 years and >25 years).

Main Results:

• The AC2 assay demonstrated high accuracy for CT and GC detection in SP samples: CT sensitivity 89.3%, CT specificity 100.0%, GC sensitivity 100.0%, GC specificity 100.0%.
• CT sensitivity was higher in patients 25 years or younger (93.1%) compared to those over 25 years (80.7%), a statistically significant difference (P = 0.02).

Conclusions:

• The AC2 assay is sufficiently sensitive and specific for screening CT and GC using 1.5 ml SP samples transferred within seven days.
• CT sensitivity may be reduced in older patients (>25 years); further research is needed for samples stored longer in SP fixative.
• Utilizing live pathology databases facilitates clinical studies efficiently, avoiding costly prospective trials.