TABLE 5.

Comparative strengths and weaknesses of 24-hour urinary albumin excretion, albumin:creatinine ratio, and urinary albumin concentration as measures of albumin level in population research, International Study of Macronutrients and Blood Pressure, 1996–2002

Comparison	Albumin measure
	24-hour urinary albumin excretion (gold standard)	Albumin:creatinine ratio	Urinary albumin concentration
General comparisons
Cost of supplies	High	Low	Low
Laboratory tests involved	Albumin	Albumin, creatinine	Albumin
Staff requirements	High	Low	Low
Convenience of collection	Low	High	High
Potential for timing errors	Yes	No	No
Potential for incompleteness	Yes	No	No
Quality control requirements	High	Low	Low
Requirements for defining micro- and macroalbuminuria	Single set of cutoff points	Gender-specific cutoff points, possibly age- and ethnicity-specific also	Single set of cutoff points
Usable literature definitions of micro- and macroalbuminuria	Yes	Yes, if gender-specific; age range not too broad	Yes
INTERMAP* comparisons†
Average correlation with 24-hour albumin excretion		0.945	0.845
Agreement with micro- and macroalbuminuria defined by 24-hour albumin excretion (κ)		0.935	0.872
Mean within-person coefficient of variation‡ (%)	37.6	37.9	35.5
Average correlation with systolic blood pressure	0.289	0.265	0.293
Average correlation with diastolic blood pressure	0.216	0.188	0.230
Average correlation with body mass index	0.211	0.118	0.188

^*INTERMAP, International Study of Macronutrients and Blood Pressure.

^†A total of 1,933 men and women were included in all comparisons except that for the kappa statistic.

^‡Weighted average of the sex-specific coefficients of variation presented in table 3.