Abstract

CHAVES-CHAVARRIA, Alicia; VARGAS-UMANA, Marianela; SCHOSINSKY-NEVERMANN, Karl  and  JIMENEZ-DIAZ, Manuel. Evaluación de un método enzimático colorimétrico para la cuantificación de colesterol sérico. Rev. costarric. cienc. méd [online]. 1997, vol.18, n.1, pp.30-43. ISSN 0253-2948.

A colorimetric method based on the Trinder reaction for use in enzymatic determination of serum cholesterol is evaluated. Two mL of working reagent, previously prepared, is mixed with 20 µK if serum and the absorbance is read against blank reagent at 500nm, after 15 minutes of incubation al 37º C. The analytical range is 25 to 600 mg/dL. Comparisons of results with total serum cholesterol by extraction gave a linear regression of Y= -0.4223 + 0.8907 (X), with a correlation coefficient (r) of 0.958 and a standard error (Sy/x) of 24 mg/dL. Comparisons with results by Colesterol Fast Color gave a linear regression of Y= 19.5 + 1.02 (X), a correlation coefficient (r) of 0.972 and a standard error (Sy/x) of 13 mg/dL and comparisons with results by Colestat gave a linear regression of Y = 19.5 + 1.02(X), a correlation coefficient (r) of 0.972 and standard error (Sy/x) of 13 mg/dL. Hemoglobin and acetylsalicylic acid do not interfere up to 50 mg/dL. L-ascorbic acid interferes equimolecularly and one mg/dL of bilirrubin causes and interference of 0.42 percent. The working reagent, stored in an amber-colored bottle, is stable for at least 3 weeks at 2-8º C. The reagent is stable for at least one year if the concentrated enzime solution is stored lyophilized or at -70º C, and ofr at least twomonths al +4º C. The optimun reagent concentration includes 4-aminophenazone 1,5 mmol/L, Triton X-100 0.5 g/L, sodium cholate 3,0 mmol/L potassium ferrocyanide 16 µmol/L, phenol 15 mmol/L, peeroxidase 1000 U/L, cholesterol oxidase 250 U/L and cholesterol ester hydrolase 500 U/L.

Keywords : serum cholesterol; serum lipids; coronary artery disease.