Application of Average of Normals (AON) for evaluation of short-term analytic performance of vitamin B12 measurements [Vitamin B12 ölçümlerinin kisa dönemli analitik performansinin deǧerlendirilmesinde normallerin ortalamasi (AON) uygulamasi]
Inal B.B.,Merkez Biyokimya Laboratuvar |
Usta M.,Merkez Biyokimya Laboratuvar |
Aral H.,Merkez Biyokimya Laboratuvar |
Tuhral C.,Merkez Biyokimya Laboratuvar |
And 2 more authors.
Turkish Journal of Biochemistry | Year: 2010
Objectives: In this study we used averages of normals technique to evaluate the analytical performance of vitamin B12 measurements. Additionally, this study is a preliminary work for verifying of reference interval given in kit insert. Material and Methods: Serum vitamin B12 measurements (n=2106) were performed using Roche E170 immunochemistry analyzer. By using explore analysis in SPSS 11.5 program, outliers were eliminated and using this normalized data (n=1884) mean value (Xpopulation), standard deviation (S population) and Spopulation/Smeasurement ratio were calculated. Minimum patient number was calculated with the formula of Npopulation = 2 x Nc x (Spop / S meas)2. Truncation limits and control limits were calculated using Xpop ± 2 Spop , and X pop ± 2.58 Spop / Npop (1/2) formulas. Results: The mean value was 323 pg/mL; truncation limits were 56.8 pg/mL as the lower limit and 628 pg/mL as the higher limit. Control limits calculated by using Xpop±2.58 Spop/(N pop)1/2 formula were 333 pg/mL as the lower limit and 351 pg/mL as the higher limit. Conclusions: In our opinion, this cost-effective technique can be used as an adjunctive control procedure to conventional QC applications in monitoring laboratory performance in terms of analytic stability. © TurkJBiochem.com.