Evaluation of AutoLab Rapid Plasma Reagin and AutoLab Treponema pallidum Latex Agglutination for Syphilis Infection Testing

Park, Mi Jung; Park, Pil Whan; Seo, Yiel Hea; Ahn, Jeong Yeal; Kim, Kyung Hee; Seo, Ja Young; Jeong, Ji Hun; Kim, Moon Jin; Lee, Hwan Tae

Abstract

BACKGROUND
Automated assays have recently been developed for efficient serological testing of syphilis infection. Here, we evaluate the performance of new automated serological assays for syphilis infection.
METHODS
The precision, linearity, and detection limit of the automated kits AutoLab rapid plasma reagin (RPR) (IVD-RPR) and AutoLab (Treponema pallidum Latex Agglutination) TPLA (IVD-TPLA) (IVDLab Co., Korea) were evaluated using an immunoturbidimetric method. In addition, the results of these tests were compared with those obtained using the HiSens Auto RPR LTIA (HBi-RPR) and HiSens Auto TP LTIA (HBi-TPLA) tests (HBi Co., Korea) with 122 serum samples.
RESULTS
Both the IVD-RPR and IVD-TPLA kits showed acceptable precision for the positive controls (IVDLab Co., Korea). The within-run and total precision of IVD-RPR were better than those of HBi-RPR at cut-off levels (CV, 7.0% to 7.4% for IVD-RPR; CV, 33.3% to 40.0% for HBi-RPR). The IVD-RPR and IVD-TPLA kits demonstrated acceptable linearity and limits of detection. The agreement rate between IVD-RPR and HBi-RPR was 83.60% (102/122). Nineteen samples were IVD-RPR negative but HBi-RPR positive; 12 of these were from patients with a history of syphilis. The agreement rate between IVD-TPLA and HBi-TPLA was 96.72% (118/122). All discrepant results were IVD-TPLA positive and HBi-TPLA negative.
CONCLUSIONS
IVD-RPR and IVD-TPLA exhibited acceptable precision, linearity, and limits of detection for the diagnosis of syphilis infection. IVD-RPR was suitable for monitoring syphilis infections with good precision that was near cut-off levels. IVD-TPLA was useful for detecting primary syphilis infection.