Original Article

Ann Lab Med 2015; 35(1): 50-56

Published online January 1, 2015

Copyright © Korean Society for Laboratory Medicine.

Highly Sensitive and Novel Point-of-Care System, aQcare Chlamydia TRF Kit for Detecting Chlamydia trachomatis by Using Europium (Eu) (III) Chelated Nanoparticles

Ji Yeon Ham, M.D.1, Jaean Jung, M.S.2, Byung-Gap Hwang, Ph.D.2, Won-Jung Kim, Ph.D.2, Young-Seop Kim, Ph.D.2, Eun-Ju Kim, M.S.2, Mi-Yeon Cho, M.S.2, Mi-Sun Hwang, Ph.D.2, Dong Il Won, M.D.1,3, and Jang Soo Suh, M.D.1,3

Department of Laboratory Medicine1, Kyungpook National University Hospital, Daegu; Medisensor Inc.2, Daegu; Department of Clinical Pathology3, Kyungpook National University School of Medicine, Daegu, Korea

Correspondence to: Jang Soo Suh
Department of Laboratory Medicine, Kyungpook National University Hospital, 130 Dongdeok-ro, Jung-gu, Daegu 700-721, Korea
Tel: +82-53-420-5293
Fax: +82-53-426-3367

Received: March 12, 2014; Revised: May 12, 2014; Accepted: October 13, 2014

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background: The bacterium Chlamydia trachomatis is one of the leading causes of sexually transmitted diseases worldwide. Since no simple and effective tool exists to diagnose C. trachomatis infections, we evaluated a novel point-of-care (POC) test, aQcare Chlamydia TRF kit, which uses europium-chelated nanoparticles and a time-resolved fluorescence reader. Methods: The test performance was evaluated by comparing the results obtained using the novel POC testing kit with those obtained using a nucleic acid amplification test (NAAT), using 114 NAAT-positive and 327 NAAT-negative samples. Results: The cut-off value of the novel test was 20.8 with a detection limit of 0.27 ng/mL. No interference or cross-reactivity was observed. Diagnostic accuracy showed an overall sensitivity of 93.0% (106/114), specificity of 96.3% (315/327), positive predictive value (PPV) of 89.8% (106/118), and negative predictive value (NPV) of 97.5% (315/323). The sensitivity of the novel test was much higher than that of currently available POC tests. Furthermore, the relative ease and short turnaround time (30 min) of this assay enables C. trachomatis-infected individuals to be treated without a diagnostic delay. Conclusions: This simple and novel test is a potential tool to screen a larger population, especially those in areas with limited resources.

Keywords: Chlamydia trachomatis, Europium, Point-of-care systems