科研之友
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摘要
background: diabetic nephropathy (dn) affects up to 40% of diabetic patients and must be screened by the measurement of urinary albumin with a sensitive quantitative method. objective: to evaluate the impact of different immunoturbidimetric methods to measure albuminuria in the classification of dn stages. material and method: albumin was measured in 167 urine samples (65 24 h samples and 102 casual samples) by two immunoturbidimetric methods: aptec biosys, adviaˋ 1650 bayer (albuadvia) and malb urin-pack bayerˋ, cobasmiraˋ roche (albucobas). albucobas was definedas the comparative method used to classify the samples in: normoalbuminuric (albuminuria 300 mg/24 h or %26gt; 174 mg/l; n = 31). the intra and interassay coefficients of variation (cvs), sensitivity and linearity of each method were calculated and the analytical and diagnostic agreements were analyzed by deming%26apos;s regression and bland-altman plots and by kappa coefficient, respectively. results: the intra and interassay cvs were %26lt; 5% for both methods. the sensitivity was 5 mg/l for both methods and the linearity was 160 mg/l for albucobas and 200 mg/l for albuadvia. the analytical agreement between the two methods was satisfactory (mean differences between methods = -7.68 mg/l (-0.21 - 15.2); r = 0.989; p %26lt; 0.001) and the kappa coefficient (0,914; p %26lt; 0,001) was excellent. only nine urine samples (5,4%) were in disagreement with albucobas classification: six microalbuminuric samples were misclassified as normoalbuminuric (n = 3) and macroalbuminuric (n = 3) by albuadvia. three normoalbuminuric samples were misclassified as microalbuminuric by albuadvia. the albumin values of these samples were in the highest diagnostic adopted cut-off point for each dn stage. conclusion: the immunoturbidimetric methods analyzed may be interchangeable, without significant misclassification of t
