VALIDATION OF ICE- SYPHILIS ELISA METHOD IN NAKASERO BLOOD BANK, UGANDA Presented By: Wilson Wambi

Authors Wilson Wambi 1, Ronald Ayikobua 2, Gilbert Sunday 3 1 Laboratory Quality Officer, Uganda Blood Transfusion Service 2 Laboratory Scientist, Uganda Blood Transfusion Service 3 Equipment and Logistics Officer, Uganda Blood Transfusion Service

Introduction Syphilis is a disease caused by a bacterium Treponema pallidum. It’s one of the infections transmitted through blood transfusion and its mandatory to be screened for in all the donated blood, therefore it needs a method that is highly sensitive (≥ 99%), specific (≥98%) with high-quality operational characteristics in terms of ease of use on large number of samples with low TAT, technical complexity, inter and intra reader variability. Four assays were used in the study, these included, ICE-Syphilis ELISA (Murex), BIOLINE Syphilis (SD), CMIA-Syphilis (ABBOTT) & TPHA which was taken as the gold standard method.

Method A laboratory based descriptive study was conducted. A total of 180 samples of known status using TPHA were used in the study, out of these samples 23, 6, 151 & 0 samples selected were true positives, false positives, True negatives & false negatives respectively. The assays were performed according to the manufactures’ instructions from the test inserts. The test methods included; TPHA, ICE-Syphilis ELISA (Murex), Bio-line Syphilis (SD) & CMIA-Syphilis (Architect).

Results All the methods evaluated had the same sensitivity and specificity of 100% and 96.2% respectively as compared to the manufacturers test performance characteristic for CMIA, >99% and >99%, ICE-ELISA (MUREX), 99.95% and 100%, TPHA,100% and 99.5%, BIOLINE (SD),99.5% and 99.3% and the previous studies. CMIA, 100% and 99.1%, ICE-ELISA (MUREX), 98.2% and 94.9%, TPHA,88% and 95%, BIOLINE (SD),94.2% and 99.2% for sensitivity and specificity respectively as shown in the tables below

Findings of the evaluation METHODRESULTS TOTAL True PositiveTrue Negative False Positives False Negatives TPHA ICE-ELISA ARCHITECT- SYPHILIS BIOLINE (SD)

Previous Studies Done METHODSENSITIVITYSPECIFICITYREFERENCES ARCHITECT SYPHILIS100%99.1%YOSHIOLEA et Al 2007 ICE-ELISA (MUREX)98.2 – 100%94.9 – 100%COLE et Al 2007 TPHA88%95%Lam et Al 2010 BIOLINE (SD)94.2 – 95.0%99.2 – 100%Herring et Al 2006

Manufacturer’s insert METHODSENSITIVITYSPECIFICITY ARCHITECT SYPHILIS≥ 99%≥ 99.1% ICE-ELISA (MUREX)100%99.95% TPHA99.5%100% BIOLINE (SD)99.3%99.5%

Discussion The sensitivity in the study was 100% which is comparable with the previous studies conducted by COLE et al (2007) on ICE- Elisa method and the manufacturer performance characteristics (table 4). Screening for syphilis infection in blood transfusion set up requires a highly sensitive method that is capable of detecting the initial (primary) stages of Treponema infection especially in donor blood which is meant for transfusion to patients in the hospitals. The specificity in the study was 96.2% which is comparable to studies by Cloe et al (2007) but slightly lower than manufacturer performance characteristics (99.95%).

Conclusion and Recommendation In the study it was evidenced that the all screening methods evaluated are equally sensitive and specific despite the performance characteristic, ICE- ELISA method is more convenient in terms of use, volume of work, turnaround times and poses no technical complexity as compared to the other methods. Based on the overall evaluation ICE-ELISA was highly recommended for syphilis screening in a blood transfusion set up.

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