Ocular Microbiology and Immunology Group
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2014 OMIG Abstract 1

Gen-Probe^® Aptima^® is a Validated New Nucleic Acid Amplification Test (NAAT) for Detecting Chlamydia trachomatis from Ocular Samples
Regis P. Kowalski, MS, M[ASCP]; Lisa M. Karenchak, BS, M[ASCP]; Leela V. Raju, MD,
and Nahed Ismail, MD, PhD.
The Charles T. Campbell Ophthalmic Microbiology and the Division of Clinical Microbiology, UPMC,
University of Pittsburgh; Pittsburgh, PA

Purpose: Chlamydia conjunctivitis may have chronic symptoms and have social ramifications. This study presents a validation of Gen-Probe^® Aptima^® Combo 2 assay for detection of ribosomal RNA of Chlamydia trachomatis (CT) from direct ocular samples.

Methods: A battery of 25 true-positive specimens (direct ocular specimens previously PCR positive for chlamydia) and 25 true-negative specimens (direct ocular specimens culture-positive for HSV (5), Adenovirus (5), Haemophilus influenzae (5), Streptococcus pneumoniae (5) and transport medium (5)) were tested for Chlamydia trachomatis by the Gen-Probe^® Aptima^® Combo 2 assay. The 25 chlamydia PCR-positive (obtained May 1994 to May 2012) and 20 true-negative ocular specimens (obtained December 2008 to August 2013) were collected with soft-tipped applicators and placed in Bartels Chlamydia Transport Medium. All specimens were stored at -80^oC. Prior to testing, all samples were centrifuged at 13,000 rpm for one hour at 6^oC. For each sample, using the Aptima^® Unisex blue swab, a specimen was collected from the conical apex of the storage tube where a pellet was formed. The Aptima^® Unisex swab was placed in a tube of Aptima^® transport medium for testing.

Results: Out of 25 true-positive samples, 24 (96%) were positive by NAAT while 25 of 25 true-negatives (100%) tested negative. The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were determined, respectively, to be: 96%, 100%, 100%, 96%, and 98%.

Conclusions: Gen-Probe^® Aptima^® Combo 2 assay for rRNA detection of CT in ocular specimens was optimal for laboratory diagnosis. Further confirmation of validation using more samples is warranted. This study emphasizes the importance of saving excess direct samples for testing validation.

Disclosure: N

2014 Agenda and Abstracts | Next >