In the ELISA test for the assessment of rabies antibodies the authors observed dishomogeneity of microtitration plates from different producers. The same conditions for the test in all wells of the microtitration plates were provided. Results of the investigations proved, that the deviation from the average value of absorbance is highest in the farthest positions of microtitration plates (lines A and H, columns 1 and 12). Statistically significant deviations were detected also in these positions most frequently. Observation of the deviations number sign indicated that the tested types of microtitration plates are divided into potentially „positive“ and „negative zones“. Measurement errors followed from the mentioned factors can be minimized by correct arrangement of samples in the ELISA test.

        Key words: microtitration plate, deviation of measurement.