Table 2.

Performance of different approaches to predict 24-hour urine excretion based on spot urine samples

Variable	Lin's CCC	95% CI	Bias (mg/24 hour)	95% LoA (mg/24 hour)	P30
Oxalate
Prediction 1	0.66	0.55–0.78	−3.0	−48.7–42.6	58.1
Prediction 2	0.63	0.52–0.74	−4.9	−56.1–46.2	50.0
Prediction 3	0.48*, **, ***	0.35–0.62	−15.6	−50.7–19.6	29.7
Prediction 4	0.62	0.48–0.76	−4.0	−46.6–38.7	47.3
Calcium
Prediction 1	0.63	0.50–0.75	19	−191–229	44.6
Prediction 2	0.63***	0.49–0.77	−4	−184–176	44.6
Prediction 3	0.47*, **	0.31–0.62	−52	−227–123	36.5
Prediction 4	0.54	0.38–0.70	12	−201–226	37.8
Magnesium
Prediction 1	0.66	0.54–0.77	15	−79–109	51.4
Prediction 2	0.66***	0.52–0.78	3	−80–87	51.4
Prediction 3	0.31*, **	0.15–0.47	−28	−119–63	35.1
Prediction 4	0.41	0.22–0.60	8	−97–113	37.8
Citrate
Prediction 1	0.82	0.75–0.90	−38	−374–297	73.0
Prediction 2	0.67*	0.54–0.79	−77	−497–344	55.4
Prediction 3	0.48*, **, ***	0.35–0.61	−200	−616–216	40.5
Prediction 4	0.64*	0.51–0.77	−25	−525–474	47.3
Uric acid
Prediction 1	0.52	0.36–0.68	−52	−484–380	60.8
Prediction 2	0.30*	0.10–0.49	−94	−587–398	59.5
Prediction 3	0.05*, **	0–0.16	−237	−709–234	24.3
Prediction 4	0.09*	0–0.31	−61	−623–501	55.4

*P < 0.05 versus Prediction 1; **P < 0.05 versus Prediction 2; ***P < 0.05 versus Prediction 4.