Evaluation of the diagnostic performance of the Standard M10 MDR-TB PCR system in pulmonary tuberculosis and comparison with the Xpert MTB/RIF Ultra system

Abstract

Objectives: Rapid diagnosis is critical for tuberculosis control. Xpert MTB/RIF Ultra is a widely used PCR system known for its simplicity, ease of application, and accuracy. STANDARD M10 MDR-TB is a recently introduced diagnostic test with a similar operating principle, used for the detection of M. tuberculosis complex. Our study aimed to evaluate this newly introduced test by comparing it with Xpert MTB/RIF Ultra. Methods: Our study included 25 (50 in total) clinical samples, each with positive and negative PCR results, that were accepted to the medical microbiology laboratory between May 2023 and February 2024 and evaluated with Xpert MTB/RIF Ultra. All samples were also evaluated with STANDARD M10 MDR-TB, culture, and AFB microscopy. Results: Of the collected samples, eight were detected positive by acid-fast bacilli (AFB) microscopy, 20 by culture, and 22 by the STANDARD M10 MDR-TB test. When culture was considered the gold standard, the sensitivity, specificity, PPV, and NPV of the Xpert MTB/RIF Ultra device were 100%, 83.3%, 80%, and 100%, respectively. When culture was considered the gold standard, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the STANDARD M10 MDR-TB device were 90%, 86.6%, 81.8%, and 92.8%, respectively. When results were analyzed using Cohen's Kappa test, a very high level of agreement (κ=0.88) was detected between both PCR systems. Conclusion: The STANDARD M10 MDR-TB test may have a potential to be routinely used in microbiology laboratories for the detection of tubercle bacilli in clinical samples because of its high sensitivity, specificity and rapid turnaround time.

Keywords

• PCR
• Diagnosis
• Tuberculosis

Akciğer tüberkülozu tanısında Standard M10 MDR-TB PCR sisteminin performansının değerlendirilmesi ve Xpert MTB/RIF Ultra sistemiyle karşılaştırılması

Abstract

Amaç: Hızlı tanı tüberküloz kontrolü için kritik öneme sahiptir. Xpert MTB/RIF Ultra testi, basitliği, uygulama kolay-lığı ve doğru sonuç verme kapasitesiyle bilinen yaygın olarak kullanılan bir PCR sistemidir. STANDARD M10 MDR-TB ise son dönemde piyasaya sürülen, benzer çalışma prensibine sahip, M. tuberculosis kompleksini tespit etmek için kullanılan bir tanı testidir. Çalışmamızda yeni kullanıma giren bu testin, Xpert MTB/RIF Ultra ile karşılaştırılarak sonuçların değerlendirmesi amaçlanmaktadır. Yöntem: Çalışmamıza, Mayıs 2023-Şubat 2024 tarihleri arasında tıbbi mikrobiyoloji laboratuvarına kabul edilen ve Xpert MTB/RIF Ultra ile değerlendirilerek PCR sonucu pozitif ve negatif olan 25’er (toplamda 50) klinik numune dahil edilmiştir. Numunelerin tamamı STANDARD M10 MDR-TB, kültür ve aside dirençli basil boyama (ARB) mikroskopi ile de değerlendirilmiştir. . Bulgular: Toplanan numunelerden 8’i ARB mikroskopi ile, 20’si kültür ile, 22’si STANDARD M10 MDR-TB sistemi ile pozitif olarak saptanmıştır. Kültür altın standart olarak kabul edildiğinde Xpert MTB/RIF Ultra testinin duyarlılık, özgüllük, pozitif prediktif değer (PPD) ve negatif prediktif değer (NPD) değerleri sırasıyla %100, %83,3, %80 ve %100’dür. Yine kültür altın standart olarak kabul edildiğinde STANDARD M10 MDR-TB testinin duyarlılık, özgül-lük, PPD ve NPD değerleri sırasıyla %90, %86,6, %81,8 ve %92,8 olarak saptandı. Cohen’s Kappa testi ile analiz ya-pıldığında, her iki PCR sistemi arasında çok yüksek düzeyde uyum (κ=0.88) tespit edildi. Sonuç: STANDARD M10 MDR-TB testi, klinik numunelerde tüberküloz basili tespitinde, duyarlılık ve özgüllüğünün yüksek olması ve kısa sürede sonuç verebilmesinden dolayı, mikrobiyoloji laboratuvarlarında rutin olarak kullanım potansiyeli sunmaktadır.

Keywords

• PCR
• tanı
• Tüberküloz

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