Lab Med Online.  2018 Jul;8(3):87-93. 10.3343/lmo.2018.8.3.87.

Comparison of Auto RPR Plus and Auto TPIM Plus with Mediace RPR and Abbott Syphilis TP for Serologic Diagnosis of Syphilis

• Kim HJ
• Nah EH
• Cho S
• Jeong SY

• KMID: 2414129
• DOI: http://doi.org/10.3343/lmo.2018.8.3.87

Abstract

BACKGROUND
Serologic testing is considered a standard method for syphilis diagnosis. We compared Auto RPR Plus and Auto TPIM Plus with previously developed assays.
METHODS
The precision around the cut-off, linearity, and recovery rate of Auto RPR Plus and Auto TPIM Plus was evaluated using their positive/negative control materials. The results of these two tests were compared with those of Mediace RPR and Abbott Syphilis TP using 431 remnant serum samples collected from people who underwent medical examinations.
RESULTS
The within-run precisions (coefficient of variation, CV values) of negative/positive control materials of Auto RPR Plus, Mediace RPR, Auto TPIM Plus and Abbott Syphilis TP were 15.7/2.3%, 20.4/2.3%, -/2.7%, and 8.5/2.3%, respectively; between-run precisions were 67.7/3.3%, 39.1/3.4%, -/4.0%, and 7.0/1.5%, respectively. Auto RPR Plus showed better precision around the cutoff level (1.0 U) compared to Mediace RPR (7.2-7.3% vs. 12.2-14.3%). The CVs of Auto TPIM Plus around the cutoff (10.0 U) were 13.5% at 10.5 U and 6.6% at 12.5 U. Agreement rates between Auto RPR Plus and Mediace RPR and between Auto TPIM Plus and Abbott Syphilis TP were 97.2% and 98.4%, respectively. However, twelve samples showed discrepant results for Auto RPR Plus (−)/Mediace RPR (+) and false-positive Mediace RPR results could not be excluded around the cutoff of 1.0 U.
CONCLUSIONS
Auto RPR Plus showing good precision near the cutoff can be used for syphilis screening in health checkups. However, Auto TPIM Plus needs improvement in precision and adjusting the cutoff to be used for syphilis screening.

Keyword

Syphilis; Serodiagnosis; Auto RPR Plus; Auto TPIM Plus

MeSH Terms

Diagnosis*
Mass Screening
Methods
Serologic Tests
Syphilis*

Figure

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  Fig. 1. Linearity of Auto RPR Plus test (A) and Auto TPIM Plus test (B).

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  Fig. 2. Linear regression of two quantitation RPR tests (A) and Bland-Altman plot of Auto RPR Plus and Mediace (B).

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