Impact of storage time of fresh serum samples on rapid test results of HBsAg
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Tarih
2014
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info:eu-repo/semantics/openAccess
Özet
Amaç: Hepatit B enfeksiyonun tanısında kullanılan yöntemlerden olan hızlı testler hepatit B yüzey antijenini (HBsAg) saptamaktadır. Bu testlerde, örneklerde işlem öncesi geçen sürenin sonuca olumsuz etki edip etmediğinin bilinmesi önemlidir. Bu çalışmada, oda ısısında veya +4 °C’de farklı sürelerde bekletilmiş serum örneklerinin HBsAg hızlı test sonuçlarına etkisinin incelenmesi amaçlandı. Gereç ve Yöntemler: Çalışma için toplam 51 serum örneği kullanıldı. Örnekler laboratuvarımıza ilk geldiğinde kemilüminesans metodu ile HBsAg testleri çalışıldı. Bu testler sonucunda negatif olan 30 örnek kontrol grubu olarak, pozitif sonuçlanan 21 örnek ise çalışma grubu olarak ayrıldı. Tüm örnekler bekletilmeden hızlı HBsAg testi çalışıldı. Daha sonra örneklerin her biri ikiye bölünüp alikotlandı ve yine ikişer gruba ayrıldı; birinci grup oda ısısında, ikinci grup ise buzdolabında +4 °C’de bekletildi. İlk testlerden 2-3 saatlik bir zaman geçtikten sonra bekletilen tüm örnekler için hızlı testler yeniden uygulandı ve ardından aynı koşullarda bekletilmeye devam edildi. İlk testlerden toplam 24 saat geçtikten sonra tüm örnekler için hızlı testler 3. kez çalışıldı. Test sonuçları “negatif” ile “+++” arasında skorlanarak sonuçlandırıldı. Bulgular: İlk yapılan hızlı testlerde duyarlılık oranı %85,7; özgüllük oranı %100 olarak bulundu. Bu testlerde örneklerin pozitiflik dereceleri ile ortalama HBsAg değerleri istatistiksel olarak ilişkili bulundu (p<0,001; r=0,831). Pozitiflik dereceleri bakımından, ikinci saat testleri için uyumluluk %96,1 (49/51) olarak hesaplandı. Farklı iki ısı ortamında 24 saat bekleyen örneklerde ise uyumluluk oranının %84,3’e (43/51) gerilediği görüldü, toplam sekiz örneğin pozitiflik derecesinin bir derece indiği gözlendi. Tüm testlerde ilk hızlı test sonuçlarına göre hiçbir yalancı pozitifliğe ve yalancı negatifliğe rastlanmadı. Ayrıca oda ısısı ve +4 °C’de bekletilen örneklerin test sonuçlarının birbirleriyle tam olarak örtüştüğü; farklılığın sadece bekletilen süreden kaynaklandığı sonucu ortaya çıktı. Sonuç: Sonuç olarak, çalışamızda ulaşılan bu veriler, hızlı HBsAg testi yapılacak olan durumlarda örneklerin birkaç saatten fazla bekletilmemesi gerektiğini, bir günlük bekletmenin sonucun güvenilirliğini azalttığını gösterdi.
Objective: Rapid tests, amongst the methods used in the diagnosis of hepatitis B virus infection, detect hepatitis B surface antigen (HBsAg). It is important to know whether the elapsed time between sample collection and the process has negative impact on the test results. It was aimed to evaluate the impact of samples stored either at room temperature (RT) or at +4 °C for different durations on rapid test results. Materials and Methods: A total of 51 serum samples were used. HBsAg tests were performed at the time the samples arrived at our laboratory using chemiluminescence method. 21 samples positive for HBsAg were accepted as the study group, and 30 negative samples were the controls. All the samples were tested immediately using rapid assay. Then the samples were divided into two aliquots and divided again into two groups; the first group was stored at RT, and the second was stored at +4 °C. Two or three hours after the first tests, all the samples were tested again using rapid assay, and then, they were continued to be stored; and after 24 hours, the tests were repeated for the third time. Test results were scored between “negative” and “+++”. Results: In the initial rapid tests, the sensitivity rate was 85.7%, and the specificity was 100%. A statistically significant association was found between the positivity grades and the mean HBsAg levels (p<0.001; r=0.831). The accuracy was found to be 96.1% (49/51) for the second hour tests in terms of positivity grades. It was observed that the accuracy rate was decreased to 84.3% (43/51) in samples stored for 24 hours in both conditions, and positivity grades of eight samples were decreased for one degree for each. Amongst all tests, no false negative and false positive results were obtained according to the initial tests. In addition, it was found that all the results of the samples stored either at RT or +4 °C overlapped, and that the difference was caused just by the duration of storage. Conclusion: In conclusion, sera should not be stored for long time in cases they will be tested using HBsAg rapid assays, and storage of the samples for one day decrease the reliability of the results.
Objective: Rapid tests, amongst the methods used in the diagnosis of hepatitis B virus infection, detect hepatitis B surface antigen (HBsAg). It is important to know whether the elapsed time between sample collection and the process has negative impact on the test results. It was aimed to evaluate the impact of samples stored either at room temperature (RT) or at +4 °C for different durations on rapid test results. Materials and Methods: A total of 51 serum samples were used. HBsAg tests were performed at the time the samples arrived at our laboratory using chemiluminescence method. 21 samples positive for HBsAg were accepted as the study group, and 30 negative samples were the controls. All the samples were tested immediately using rapid assay. Then the samples were divided into two aliquots and divided again into two groups; the first group was stored at RT, and the second was stored at +4 °C. Two or three hours after the first tests, all the samples were tested again using rapid assay, and then, they were continued to be stored; and after 24 hours, the tests were repeated for the third time. Test results were scored between “negative” and “+++”. Results: In the initial rapid tests, the sensitivity rate was 85.7%, and the specificity was 100%. A statistically significant association was found between the positivity grades and the mean HBsAg levels (p<0.001; r=0.831). The accuracy was found to be 96.1% (49/51) for the second hour tests in terms of positivity grades. It was observed that the accuracy rate was decreased to 84.3% (43/51) in samples stored for 24 hours in both conditions, and positivity grades of eight samples were decreased for one degree for each. Amongst all tests, no false negative and false positive results were obtained according to the initial tests. In addition, it was found that all the results of the samples stored either at RT or +4 °C overlapped, and that the difference was caused just by the duration of storage. Conclusion: In conclusion, sera should not be stored for long time in cases they will be tested using HBsAg rapid assays, and storage of the samples for one day decrease the reliability of the results.
Açıklama
Anahtar Kelimeler
Rapid Test, HBsAg, Storage Time, Storage Conditions, HBV, Hızlı Test, HBsAg, Bekleme Süresi, Bekleme Koşulları, HBV
Kaynak
Viral Hepatitis Journal
WoS Q Değeri
Scopus Q Değeri
Cilt
20
Sayı
2
