urine albumin-to-creatinine ratio

Q: At what urine albumin-to-creatinine ratio albuminuria may become significant?

Answer: 30

It is recommended that at least 2 out of 3 specimens fall within the moderately increased or severely increased albuminuria range over 3-6 month period. But even random, single-voided urine (preferably first morning) sample is found to have sensitivity of 100 percent for moderately increased albuminuria. 

Pitfalls: vigorous exercise within 24 hours before sample may give an erroneous result. Also, different labs may have different methods to measure the ratio. As expected value varies with muscle mass, gender, and race/ethnicity of the patient

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References:

1. Nathan DM, Rosenbaum C, Protasowicki VD. Single-void urine samples can be used to estimate quantitative microalbuminuria. Diabetes Care 1987; 10:414.

2. Jefferson IG, Greene SA, Smith MA, et al. Urine albumin to creatinine ratio-response to exercise in diabetes. Arch Dis Child 1985; 60:305.

3. Younes N, Cleary PA, Steffes MW, et al. Comparison of urinary albumin-creatinine ratio and albumin excretion rate in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study. Clin J Am Soc Nephrol 2010; 5:1235.

4. Mattix HJ, Hsu CY, Shaykevich S, Curhan G. Use of the albumin/creatinine ratio to detect microalbuminuria: implications of sex and race. J Am Soc Nephrol 2002; 13:1034.