ARCHİTECT ANTİ HCV TESTİNİN DÜŞÜK RİSKLİ POPÜLASYONDAKİ TANISAL GÜVENİLİRLİĞİ Diagnostic Reliability of Architect Anti Hcv Tests in a Low-Risk Population

OZET Amac: Calismamizda anti HCV testlerinin guvenirliligin ortaya konmasina ek olarak anti HCV testlerinin istenmesinden itibaren test sonuclarinin takibi, yorumlanmasi ve dogrulama prosedurlerine ne kadar uyuldugunu da gostermeyi amacladik. Gerecve Yontem: Retrospektif tanimlayici bir calisma olarak tasarlanan bu calismada 1 Ocak 2017 ve 31 Aralik 2017 tarihleri arasinda hastanemiz tibbi mikrobiyoloji merkez laboratuvarinda calisilan tum anti HCV test sonuclari tarandi. Bu hastalardan HCV RNA (PCR) ile dogrulama calisilan olgular calismaya alindi. Daha once tani almis ve interferon veya direk etkili ajanlar ile tedavi almis olanlar calisma disi birakildi. Tarama anti-HCV kemiluminesans mikropartikul immunoassay (Abbot®, Architect System; Germany), dogrulama ise HCV RNA polimeraz zincir reaksiyonu testi (Roche® COBAS® AmpliPrep / COBAS® Taqman® HCV Kantitatif Testi v2.0) ile yapildi. Bulgular: Toplamda calisilan 20.038 anti HCV testinde 337 pozitif sonuc saptandi. Ayni olguda birden fazla sayida calisilan testler cikarildiginda 220 anti-HCV sonucu kaldi. Bunlardan 74 tanesinin (%33.63) anti-HCV pozitif oldugu halde dogrulama yapilmadigi, 32 tanesinin ise oncesinde kronik hepatit C tanisi ile tedavi almis veya halen tedavi almakta olan hasta oldugu saptandi. Sonuc olarak PCR ile dogrulamaya gidilmis 114 naif anti-HCV pozitif olgu tespit edildi. Bu olgularin 78’i (%68.42) HCV RNA negatif yani yalanci pozitif, 36’si (%31.58) ise HCV RNA pozitif yani gercek hastalar olarak tanimlandi. Yalanci pozitif olgularda ortalama signal-to-cutoff (S/CO) degeri 3.24 ± 2.84 (min: 1.09, maks: 14.09) iken gercek pozitiflerde 14.05 ± 3.04 (min: 6.05, maks: 20.16) saptandi. 20038 hastadaki anti HCV seropozitiflik orani %0.94, gercek pozitiflik orani ise %0.18 olarak sonuclandi. Gercek pozitif olgulardan en dusugu olan 6.05 anti-HCV degerine sahip olgu akut hepatit C idi; bunun disindakilerin hepsinde anti HCV degeri 8’in uzerindeydi. Anti-HCV degeri 6’nin altinda olan tum olgularda HCV RNA degeri negatif olarak sonuclandi ve yalanci pozitif olarak degerlendirildi. Sonuc: Anti HCV testlerindeki yuksek yalanci pozitiflik oranlari ozellikle de dusuk endemik ulkelerde onemli bir sorun olarak devam etmektedir. En az bunun kadar onemli bir sorun da HCV ile ilgili tanisal bir algoritmanin klinisyenler tarafindan benimsenmemis oldugudur. Bu konuda farkindalik olusturmak adina daha genis kapsamli calismalarin yapilmasi ve tum cerrahi ve dahili branslardaki hekimlerin egitilmesi onem arz etmektedir. Anahtar Kelimeler: Anti HCV; Architect; Yalanci pozitiflik. ABSTRACT Objectives: In addition to demonstrating the reliability of Architect anti-HCV tests, we also aimed to show the compliance rates of follow-up, confirmation and interpretation procedure after planning anti-HCV tests. Materials and Methods: In this descriptive study, anti-HCV test results of the medical microbiology laboratory at our hospital between 1 January 2017 and 31 December 2017 were analyzed retrospectively. Cases with HCV RNA (PCR) were included in the study. Patients who were previously diagnosed with HCV and treated with interferon or direct active agents were excluded from the study. Screening was performed by anti-HCV chemiluminescence microparticle immunoassay (Abbot®, Architect System; Germany), and confirmation was performed by HCV RNA polymerase chain reaction test (Roche® COBAS® AmpliPrep / COBAS® Taqman® HCV Quantitative Test v2.0). Results: There were 337 positive results in 20,038 anti-HCV tests. After removing duplicating test results, 220 positive anti-HCV results remained. Of these, 74 (33.63%) were not tested for confirmation although they were found to be anti- HCV positive, and 32 cases had been previously treated for chronic hepatitis C or were still on treatment. Finally, we had 114 naive anti-HCV positive cases that were tested for HCV RNA. 78 of these cases (68.42%) were found to be HCV RNA negative and concluded as false positive. Thirty-six cases (31.58%) were HCV RNA positive and were diagnosed as chronic active HCV. Mean signal-to-cutoff (S/CO) ratio was found to be 3.24 ± 2.84 (min: 1.09, max: 14.09) in false positive cases and 14.05 ± 3.04 (min: 6.05, max: 20.16) in true positive cases. The anti-HCV seropositivity rate in 20.038 patients was 0.94% and the true HCV positivity rate was 0.18%. The case with anti-HCV value of 6.05 was diagnosed as acute hepatitis C, the lowest S/CO rate was 8 among the rest of the true positive cases. HCV RNA was negative in all cases with anti-HCV S/CO ratio below 6 and these cases were concluded as false positive. Conclusion: False positivity remains as an important problem in Architect anti-HCV tests, especially in low endemic countries like Turkey. In addition, one of the most important problems is that a diagnostic algorithm related to HCV is not adopted by clinicians. It is crucial to create awareness among clinicians by educating them and by the regulations in hospital information systems. Key Words: Anti HCV; Architect; False positivity.