Analytical performances of sentinel and vitros direct LDL-C assay methods, and classification of hyperlipidemia
AMAÇ: Serumda LDL-C ve sdLDL-C ölçümü için basit ve doğru bir metot gereklidir. Sentinel ve Vitros direkt LDL-C ölçüm metodlarının analitik performanslarını değerlendirmeyi, bu iki direkt ölçüm metodunun LDL-C değerlerini birbirleriyle ve Friedewald formülü ile hesaplanan LDL-C değerleri ile karşılaştırmayı ve hiperlipidemili hastaların sınıflandırılmasında hangi lipit parametresinin daha uygun olacağını belirlemeyi amaçladık. YÖNTEMLER: Direkt metotların analitik performansları 60 serum örneğinde değerlendirildi. İki farklı direkt LDL-C ölçüm metodu ve Friedewald formülü ile farklı 122 serum örneğinde LDL-C hesaplandı. Bunların dışındaki 118 serum örneğinde Sentinel sdLDL-C, Vitros sdLDL-C ve diğer değerlendirilen lipit parametreleri ölçüldü. BULGULAR: Sentinel direkt LDL-C, Vitros direkt LDL-C ve Friedewald formülü ile hesaplanan ortalama LDL-C konsantrasyonları sırasıyla 152±44 mg/dL, 146±45 mg/dL ve 141±41 mg/dL’ydi, (P
Sentinel ve vitros direkt LDL-C ölçüm yöntemlerinin analitik performansları ve hiperlipidemi sınıflaması
OBJECTIVE: A simple and accurate method is necessary to measure the LDL-C and sdLDL-C in serum. We aimed to evaluate the analytical performances of Sentinel and Vitros direct LDL-C (dLDL-C) assay methods, to compare LDL-C values of these direct methods with each other and with those values calculated by Friedewald formula, and to determine which lipid parameters could be more proper for classification of patients with hyperlipidemia. METHODS: Analytical performances of direct methods were evaluated in 60 serum samples. LDL-C was determined in different 122 sera via two different direct methods and Friedewald formula. Sentinel sdLDL-C, Vitros sdLDL-C and other evaluated lipid parameters were estimated in additional 118 serum samples. RESULTS: Mean LDL-C concentrations for Sentinel dLDL-C, Vitros dLDL-C and Friedewald formula were 152±44 mg/dL, 146±45 mg/dL, 141±41 mg/dL, respectively, (P<0.001). Highly significant associations were observed between Friedewald LDL-C and both Sentinel and Vitros dLDL-C (r=0.934, r=0.936, respectively). Although within-run imprecisions for direct methods were lower than 1.42%, total imprecisions for Sentinel and Vitros dLDL-C were lower than 1.73% and 4.8%, respectively. Sentinel and Vitros dLDL-C assay methods had 11% and 17.5% systematic error, respectively. While the lowest Friedewald LDL-C concentrations were observed in hypertriglyceridemic group, the lowest sdLDL-C values were obtained in normolipidemic group, although hyperlipidemia groups were based on Friedewald LDL-C. CONCLUSION: Vitros dLDL-C did not seem to be able to meet performance criterion of NCEP ATP III for LDL-C, because total imprecision for it was more than 4%. Direct assay methods significantly overestimated LDL-C values compared with Friedewald formula. Preference of the Sentinel direct LDL-C or sdLDL-C could be more useful for evaluation of patients with hyperlipidemia.
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