Sample Dilution in Omentin Measurement

In the studies, specific enzyme linked immunoassay (ELISA) method is generally used to determinate the plasma omentin level (1,2). There may be matrix effect interferences the omentin measurement. According to international union of pure and applied chemistry, matrix effect is the combined effect of all components of the sample other than the analyte on the measurement of the quantity. In standard laboratory procedures to determinate the plasma omentin by ELISA method, various proportions of dilution should be applied to the samples to reduce matrix interference effect. If the dilution operation is performed for any reason, the measured value must be multiplied by the dilution factor in good laboratory practice. The dilution factor will be 5, if 5fold dilution is applied to samples to reduce the matrix effect. If the sought parameter is measured 23 ng/mL in diluted sample, this value is multiplied by a dilution factor and 115 ng/mL should be reported which is the real value. In one of ours study, we used the BioVendor (BioVendorLaboratomi Medicina, Brno, Czech Republic) Human Omentin-1 ELISA reagent. In standard laboratory procedure, 40-fold dilution had been applied to the samples. In this case, the results had to be multiplied by 40. In this study, the average omentin values of the patients and control group were found 606.6±313.0 ng/mL and 357.5±147.4 ng/mL respectively (3). Although study of the Omentin-1 reference range not enough, manufacturer of the reagent we used in ours study has reported the omentin-1 level approximately 480±21 ng/mL in precision analysis. It has seen that the dilution factor was taking into account in some other similar studies, when the omentin levels were analyzed (4, 5).