Table 4.

Classification according to uβ2m excretion at baseline and repeated measurement versus patient outcome in 44 patients with repeated measurements

Measurement		Outcome (n)
Baseline	Repeated	Progression	No Progression
uβ2m ≥ 1.0 μg/min	uβ2m ≥ 1.0 μg/min	11	0
uβ2m ≥ 1.0 μg/min	uβ2m < 1.0 μg/min	3	1
uβ2m < 1.0 μg/min	uβ2m ≥ 1.0 μg/min	10	2
uβ2m < 1.0 μg/min	uβ2m < 1.0 μg/min	0	17

The positive predictive value for patients with a least one measurement ≥1.0 μg/min was 89%. The negative predictive value for patients with both measurements <1.0 μg/min was 100%. Of the 11 patients who were classified as progressors and had uβ2m > 1.0 μg/min, three had a 50% rise in serum creatinine, seven had a 25% rise and serum creatinine >135 μmol/L, and one patient had severe nephrotic syndrome. uβ2m, urinary β2-microglobulin.