Is median value of double screening test regional?

Abstract

Objective: The median values of double test which is commonly used for Down Syndrome screening show diversity between countries. In this study, we aimed to investigate the possible differences in corrected multiplies of median (MoM) values of individiuals between the two cities of the same geographic region. Methods: Blood samples for double test analysis, sent from Corum and Samsun, were studied in the same laboratory. Results of double test analyses were retrospectively evaluated. Mann-Whitney U test was used for comparison of corrected MoM values of free human chorionic gonadotropin (f-? hCG) and pregnancy-specific plasma protein-A (PAPP-A) according to gestational age. Results were given as median (minimum-maximum) values. The p <0.05 was considered significant. Results: The corrected f-? hCG values obtained from Corum and Samsun were as follows: 0.75 (0.24-2.11, n=28), 0.85 (0.21-2.95, n=143) (p=0.378) in 10th gestational week; 0.75 (0.17-4.15, n=349), 0.84 (0.14-4.76, n=672) (p=0.005) in 11th gestational week; 0.81 (0.15-5.15, n=542), 0.86(0.19-5.18, n=946) (p=0.014) in 12th gestational week; 0.77 (0.20-6.32, n=365), 0.87 (0.20-5.54, n=327) (p=0.054) in 13th gestational week, respectively. Corrected PAPP-A values from Qorum and Samsun were as follows: in 10th gestational week 0.94 (0.41-5.57), 0.87(0.19-3.53) (p=0.425); in 11th gestational week 0.88 (0.21-3.61), 0.89 (0.19-3.70) (p=0.963); in 12th gestational week 0.89 (0.22-4.24), 0.90 (0.15-4.99) (p=0.704); in 13th gestational week 0.93 (0.19-2.70), 0.90 (0.09-2.80) (p=0.952) respectively. Conclusion: The MoM values of f-? hCG tests, derived from individuals from Çorum and Samsun, both located in the Central Black Sea Region, were found to be different. This finding indicates that for double test analysis, different median values may be used for patients from different cities. © 2015 Turkish Biochemistry Society. All rights reserved.

Amac: Down Sendromu taramasında sıklıkla kullanılan ikili test medyan değerleri ulkeler arasında farklılık gostermektedir. Bu calışmamızda aynı coğrafi bolgede bulunan iki ildeki bireylerin duzeltilmiş multiplies of median (MoM) değerleri arasında farklılık olup olmadığının araştırılması amaclandı. Metod: Corum ve Samsun illerinden aynı laboratuvara numune gonderilerek calışılan ikili test sonucları retrospektif olarak değerlendirildi. Serbest beta insan koryonik gonadotropin (s-β hCG) ve gebeliğe ozgu plazma protein-A (PAPP-A) testleri icin gebelik haftalarına gore elde edilen duzeltilmiş MoM değerleri Mann-Whitney-U testi ile değerlendirildi. Sonuclar medyan (minimum-maksimum) olarak verildi. p<0.05 anlamlı kabul edildi. Bulgular: Corum ve Samsun illerine ait duzeltilmiş s-β hCG MoM değerleri sırasıyla; 10. gebelik haftasında 0.75 (0.24-2.11, n=28), 0.85 (0.21-2.95, n=143) (p=0.378); 11. gebelik haftasında 0.75 (0.17-4.15, n=349), 0.84 (0.14-4.76, n=672) (p=0.005); 12. haftada 0.81 (0.15-5.15, n=542), 0.86 (0.19-5.18, n=946) (p=0.014); 13. haftada 0.77 (0.20-6.32, n=365), 0.87 (0.20-5.54, n=327) (p=0.054) olarak bulundu. Duzeltilmiş PAPP-A MoM değerleri ise sırasıyla 10. gebelik haftasında 0.94 (0.41-5.57), 0.87 (0.19-3.53) (p=0.425); 11. haftada 0.88 (0.21-3.61), 0.89 (0.19-3.70) (p=0.963); 12. haftada 0.89 (0.22-4.24), 0.90 (0.15-4.99) (p=0.704); 13. haftada 0.93 (0.19-2.70), 0.90 (0.09-2.80) (p=0.952) olarak bulundu. Sonuc: Orta Karadeniz Bolgesi’nde bulunan Corum ve Samsun illerindeki bireylerin s-β hCG testlerinden elde edilen duzeltilmiş MoM değerlerinin farklı olması, ikili tarama testi risk hesaplamalarında her il icin farklı medyan değerleri kullanılması gerekebileceğini duşundurmuştur.