Measurement of validity and uncertainty for quality control results of four live poultry vaccines were studied for calculated the difference between uncertainty measurements for different routes of inoculation, accuracy, precision attributed to different factors; personal and inoculation site.A total of (80) samples were used in this study represent to four types of vaccines; three of them were egg adapted vaccine and last one was tissue culture (TC) adapted. Four analysts were involved to assess; the repeatability, reproducibility, bias, to determine uncertainty as well as estimate the stability and homogeneity of vaccine sample. The mean titer for (Infectious bursal disease vaccine (IBD), Fowl pox (FP), Avian Encephalomyelitis (AE) and tissue culture adapted Infectious bursal disease vaccine(IBDTC) were 105.43±0.403 ,103.58 ±0.256,103.44±0.326 and 105.02±0.492 respectively. Homogeneity and stability results for all types of vaccines were accepted according to TS/ ISO22117.The reproducibility component of TC technique higher and the Bias was lower than all other egg inoculation
routes