Korean J Lab Med.  2008 Aug;28(4):312-318. 10.3343/kjlm.2008.28.4.312.

Evaluation of Performance and False Positivity of Mediace RPR Test that Uses a Chemistry Autoanalyzer

Affiliations
  • 1Department of Laboratory Medicine, Konkuk University College of Medicine, Seoul, Korea. eysongmd@hanmail.net
  • 2Department of Laboratory Medicine, Konkuk University Hospital, Seoul, Korea.
  • 3Greencross Reference Laboratory, Yongin, Korea.
  • 4Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea.

Abstract

BACKGROUND: We evaluated the performance and false positive rate of Mediace RPR test (Sekisui, Japan), a newly introduced nontreponemal test using a chemistry autoanalyzer. METHODS: The sensitivity of Mediace RPR test was analyzed using sera from 50 patients with syphilis in different stages (8 primary, 7 secondary, and 35 latent), 14 sera positive with fluorescent treponemal antibody absorption (FTA-ABS) IgM, and 74 sera positive with conventional rapid plasma regain (RPR) card test (Asan, Korea) and also positive with Treponema pallidum hemagglutination (TPHA) test or FTA-ABS IgG test. The specificity was analyzed on 108 healthy blood donors. We also performed RPR card test on 302 sera that had been tested positive with Mediace RPR test and also performed TPHA or FTA-ABS IgG test to analyze the false positive rate of Mediace RPR test. A cutoff value of 0.5 R.U. (RPR unit) was used for Mediace RPR test. RESULTS: Mediace RPR test on syphilitic sera of different stages (primary, secondary, and latent stages) and FTA-ABS IgM positive sera showed a sensitivity of 100%, 100%, 82.9% and 100%, respectively. Among the 74 sera positive with conventional RPR card test and TPHA or FTA-ABS IgG test, 55 were positive with Mediace test. The specificity of Mediace RPR test on blood donors was 97.2%. Among the 302 sera positive with Mediace RPR test, 137 sera (45.4%) were negative by RPR card and TPHA/FTA-ABS IgG tests. CONCLUSIONS: Although the sensitivities of Mediace RPR were good for primary and secondary syphilis, due to its high negative rate of Mediace RPR over the conventional RPR positive samples, further studies are necessary whether it can replace conventional nontreponemal test for screening purpose. Moreover, in view of the high false positive rate, positive results by Mediace RPR test should be confirmed with treponemal tests.

Keyword

Mediace RPR; Sensitivity; Specificity; Cutoff; False positive; Syphilis; Non-treponemal test

MeSH Terms

Autoanalysis/methods
False Positive Reactions
Humans
ROC Curve
Sensitivity and Specificity
Syphilis/*diagnosis
Syphilis Serodiagnosis/*methods

Figure

  • Fig. 1. ROC curve analysis of Mediace RPR test.

  • Fig. 2. Linearity of Mediace RPR test


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Hyun Yong Hwang, Mi Hyang Kim
Infect Chemother. 2009;41(3):154-159.    doi: 10.3947/ic.2009.41.3.154.

Comparison of Automated Treponemal and Nontreponemal Test Algorithms as First-Line Syphilis Screening Assays
Hee Jin Huh, Jae-Woo Chung, Seong Yeon Park, Seok Lae Chae
Ann Lab Med. 2016;36(1):23-27.    doi: 10.3343/alm.2016.36.1.23.

Comparison of Auto RPR Plus and Auto TPIM Plus with Mediace RPR and Abbott Syphilis TP for Serologic Diagnosis of Syphilis
Hyun-Jeong Kim, Eun-Hee Nah, Seon Cho, So-Young Jeong
Lab Med Online. 2018;8(3):87-93.    doi: 10.3343/lmo.2018.8.3.87.

Comparison of Quantitative Results among Two Automated Rapid Plasma Reagin (RPR) Assays and a Manual RPR Test
Yeong Sic Kim, Jehoon Lee, Hae Kyung Lee, Hyunjung Kim, Hi Jeong Kwon, Ki Ouk Min, Eun Joo Seo, Soo-Young Kim
Korean J Lab Med. 2009;29(4):331-337.    doi: 10.3343/kjlm.2009.29.4.331.


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