Table 15.
Intraday and interday correlation and variance of the uPCR and uACR of the same sample according to the mean uPCR values
| Mean of | Bias | Mean of | Mean of | r | p | Bias | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean of 2 uPCR | Mean of | 2 urinary protein | Regression line | of uPCR | 2 urinary albumin | 2 uACR | Regression line | of uACR | ||||||||
| (g/gCr) | n | (g/gCr) | 2 uCr/sCr | (mg/dl) | r | p | (g/gCr) | (mg/l) | (mg/gCr) | (mg/gCr) | ||||||
| Intraday | ||||||||||||||||
| 3-4 h | LPCR1-2 | < 0.15 | 63 | 0.05 (0.02–0.09) | 58.7 (38.4–97.8) | 3.1 (1.3–7.0) | 2uPCR = 0.7859 × 1uPCR + 0.001936 | 0.78 | < 0.0001 | − 0.01 (− 0.03 to 0) | 15.9 (7.1–30.8) | 22.0 (12.0–39.3) | 2uACR = 0.9843 × 1uACR − 1.229 | 0.98 | < 0.0001 | − 1.0 (− 2.0 to 0) |
| MPCR1-2 | ≥ 0.15 | 25 | 0.30 (0.21–0.46)** | 51.2 (36.1–85.1) | 22.2 (10.0–29.8)** | 2uPCR = 0.9818 × 1uPCR − 0.01493 | 0.99 | < 0.0001 | − 0.01 (− 0.03 to 0) | 154.1 (44.3–200.0)** | 192.0 (132.0–299.0)** | 2uACR = 1.018 × 1uACR − 8.972 | 0.99 | < 0.0001 | − 2.0 (− 4.0 to 0) | |
| 3 min | LPCR3-4 | < 0.15 | 65 | 0.05 (0.03–0.08) | 57.2 (38.5–100.0) | 3.0 (1.4–7.0) | 4uPCR = 0.9669 × 3uPCR + 0.003974 | 0.94 | < 0.0001 | 0(0–0.01) | 14.9 (5.8–30.9) | 21.0 (9.5–39.0) | 4uACR = 1.002 × 3uACR − 0.6946 | 0.99 | < 0.0001 | 0 (− 1.0 to 0) |
| MPCR3-4 | ≥ 0.15 | 23 | 0.31 (0.21–0.48)** | 51.9 (35.6–88.3) | 23.3 (13.7–31.8)** | 4uPCR = 1.022 × 3uPCR + 0.006523 | 0.99 | < 0.0001 | 0.02 (− 0.01 to 0.03) | 155.7 (72.7–199.2)** | 197.0 (146.0–310.3)** | 4uACR = 0.9974 × 3uACR + 0.8702 | 0.99 | < 0.0001 | 0 (− 1.0 to 3.5) | |
| Interday | ||||||||||||||||
| 3–4 days | LPCR1-3 | < 0.15 | 64 | 0.05 (0.03–0.08) | 58.8 (38.5–97.3) | 3.3 (1.4–7.2) | 3uPCR = 0.7230 × 1uPCR + 0.008293 | 0.82 | < 0.0001 | − 0.01 (− 0.02 to 0) | 15.5 (7.3–30.9) | 23.1 (12.4–40.1) | 3uACR = 0.9306 × 1uACR − 0.4581 | 0.96 | < 0.0001 | − 1.0 (− 3.3 to 1.0) |
| MPCR1-3 | ≥ 0.15 | 24 | 0.31 (0.21–0.46)** | 50.2 (35.8–87.7) | 22.8 (12.1–31.4)** | 3uPCR = 0.9773 × 1uPCR − 0.009794 | 0.99 | < 0.0001 | − 0.01 (− 0.04 to 0) | 154.5 (52.3–207.2)** | 193.8 (146.0–304.3)** | 3uACR = 1.033 × 1uACR − 10.65 | 0.99 | < 0.0001 | − 0.5 (− 4.5 to 2.0) | |
| LPCR1-4 | < 0.15 | 64 | 0.05 (0.03–0.09) | 59.9 (38.3–100.0) | 3.4 (1.5–7.3) | 4uPCR = 0.7737 × 1uPCR + 0.007619 | 0.84 | < 0.0001 | 0 (− 0.02 to 0.01) | 15.1 (6.9–30.9) | 21.6 (11.9–40.3) | 4uACR = 0.9502 × 1uACR − 1.637 | 0.96 | < 0.0001 | − 1.0 (− 3.5 to 0) | |
| MPCR1-4 | ≥ 0.15 | 24 | 0.31 (0.21–0.46)** | 50.2 (35.9–85.9) | 22.9 (11.9–30.7)** | 4uPCR = 1.002 × 1uPCR − 0.006477 | 0.99 | < 0.0001 | − 0.01 (− 0.02 to 0.02) | 152.0 (44.9–198.8)** | 194.0 (145.4–306.1)** | 4uACR = 1.030 × 1uACR − 9.879 | 0.99 | < 0.0001 | − 1.0 (− 2.5 to 3.3) | |
| 3–4 days | LPCR2-3 | < 0.15 | 63 | 0.05 (0.02–0.08) | 58.6 (38.6–97.8) | 3.1 (1.1–6.3) | 3uPCR = 0.7046 × 2uPCR + 0.01701 | 0.81 | < 0.0001 | 0 (− 0.01 to 0.02) | 14.2 (6.7–28.3) | 22.0 (10.8–38.5) | 3uACR = 0.9276 × 2uACR + 1.318 | 0.94 | < 0.0001 | 0 (− 0.5 to 2.0) |
| MPCR2-3 | ≥ 0.15 | 25 | 0.30(0.19–0.47)** | 51.6 (36.0–89.8) | 21.7 (13.3–30.8)** | 3uPCR = 0.9932 × 2uPCR + 0.005331 | 0.99 | < 0.0001 | 0 (− 0.02 to 0.02) | 154.3 (54.5–200.2)** | 190.5 (132.5–297.0)** | 3uACR = 1.015 × 2uACR − 1.886 | 0.99 | < 0.0001 | 1.0 (− 3.0 to 5.0) | |
| LPCR2-4 | < 0.15 | 65 | 0.05 (0.02–0.08) | 58.7 (38.5–99.2) | 2.9 (1.2–7.1) | 4uPCR = 0.7315 × 2uPCR + 0.01863 | 0.80 | < 0.0001 | 0 (− 0.01 to 0.02) | 14.9 (6.7–30.1) | 22.2 (11.0–40.0) | 4uACR = 0.9762 × 2uACR − 0.5351 | 0.97 | < 0.0001 | 1.0 (− 1.0 to 1.0) | |
| MPCR2-4 | ≥ 0.15 | 23 | 0.31 (0.23–0.47)** | 51.6 (35.7–87.9) | 21.9 (14.0–30.5)** | 4uPCR = 1.016 × 2uPCR + 0.01199 | 0.99 | < 0.0001 | 0 (− 0.01 to 0.05) | 155.9 (72.1–198.1)** | 193.5 (145.3–311.5)** | 4uACR = 1.013 × 2uACR − 1.315 | 0.99 | < 0.0001 | 3.0 (0–5.5)* | |
The numbers of 1, 2, 3, and 4 represent the first, second, third, and fourth measurements, respectively, of urinary protein, albumin, and creatinine. Data are presented as the median (IQR)
uCr/sCr urine-to-serum creatinine ratio; uACR, urinary albumin-to-creatinine ratio; uPCR urinary protein-to-creatinine ratio, LPCR low urinary albumin-to-creatinine ratio; MPCR medium urinary protein-to-creatinine ratio
*p < 0.01; **p < 0.001 vs. uPCR < 0.15 g/gCr by the Mann–Whitney's U test bias, difference of the later measurement against the previous measurement