Abstract

RODRIGUEZ, N; VELASQUEZ, Y; GONZALEZ, E  and  LORENTE, A. Precision and accuracy of an enzimatic method for total cholesterol determination. Mem. Inst. Investig. Cienc. Salud [online]. 2007, vol.5, n.2, pp.42-45. ISSN 1812-9528.

The coupling of enzymes cholesterol esterase, cholesterol oxydase and peroxydase is the most frequently used method to determine cholesterol. The Allain et al formulation and Roeschlau et al modification have been adapted by Heiga Laboratories in its Ref 450-L reagent to determine total cholesterol in serum; establishing the necessity of evaluating its reliability. Thus, the objective of this research is to evaluate the accuracy and precision of this method. For this, 30 consecutives determinations were carried out in control assays at two concentrations levels (NC: 193 mg/dL and AC: 247 mg/dL) and 30 addition assays (R: adding 200mg of cholesterol to NC). The intra-laboratory precision was determined using variation coefficients (VC) and the inter-laboratory precision with the Obtained Standard Deviation (OSD). The accuracy was evaluated with the recovery percentage (%R) and the percent relative deviation (PRD) of the mean obtained in relation to the NC value(established by a Reference Laboratory). The VC ranged from 0. 63% to 1.13% and the OSD between -1.70 and -0.18 and they were both considered satisfactory (VC lower than 5% and OSD between -2 and +2). The %R was 104.8% and the PRD was 0.89%, being considered acceptable because the values were between 95% and 105%, and lower than 9% respectively. It was concluded that the evaluated method shows intra-laboratory and inter-laboratory precision as well as accuracy for normal and high cholesterol levels.

Keywords : Precision; accuracy; reliability.

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