Table 1.

Precision studies results.

	XA determined by the proposed method (mg/L)*	Indirect activation coefficient (AC) test for RBC/AST**
Within-run (n = 5)*
Mean, mg/L	20.2	41.0
SD, mg/L	0.60	1.5
CV, %	3.0	3.7
Day-to-day (n = 25)**
Mean, mg/L	20.2	41.0
SD, mg/L	0.7	1.9
CV, %	3.5	4.6

*Each level of pooled urine sample was determined simultaneously for 5 times at the same day.

**Each level of pooled urine sample was run 5 times per day for five consecutive days. The pooled data were then calculated for mean, SD and CV.