The importance of a blind control in the establishment of assigned values in control sera. The establishment of assigned values in control sera, I.
We describe a study by which the establishment of assigned values of a control serum was simulated. The study covered two controls: The internal known control and a blind control. Seven constituents were analyzed in 10 or 11 laboratories, respectively, yielding a total of 72 sets of analytical values. Each set covered double determinations within approximately 18 series for each sample. The course of a blind control correlates better with the unknown sample for which assigned values are to be determined than does a known control. Out of 72 sets 5 sets were found incorrect. Out of these, 2 sets could be recognized exclusively by means of the blind control, and 2 others primarily by means of the known control; one of these could be detected by means of the double determinations. Consequently, a blind control has a greater control efficiency than double determinations.
D001774:Blood Chemical Analysis / Q000379:methods*; D006801:Humans; D012015:Reference Standards