OPEN ACCESS pISSN 2234-3806
eISSN 2234-3814

Table. 3.

Table. 3.

Percentage bias of ABCr PT survey by cumulative trial

Cumulative trial N of participating laboratories Bias (%) Difference in mean percentage bias compared with the 1st trial*


Mean (95% CI) SD Mean (95% CI) P
1st 328 5.51 (4.94–6.08) 10.87 Reference
2nd 319 4.74 (4.16–5.31) 9.95 −0.77 (−1.98–0.44) 0.584
3rd 268 4.31 (3.68–4.93) 10.61 −1.20 (−2.47–0.07) 0.081
4th 258 3.45 (2.80–4.09) 10.24 −2.06 (−3.35– −0.77) < 0.001
5th 206 3.29 (2.56–4.01) 9.44 −2.22 (−3.60– −0.84) < 0.001
6th 196 2.66 (1.91–3.40) 9.20 −2.85 (−4.25– −1.45) < 0.001
7th 172 2.60 (1.80–3.39) 8.68 −2.91 (−4.37– −1.45) < 0.001
8th 163 1.51 (0.70–2.33) 7.85 −3.99 (−5.48– −2.50) < 0.001
9th 133 2.32 (1.42–3.22) 7.14 −3.18 (−4.78– −1.59) < 0.001
10th 128 3.08 (2.17–4.00) 7.78 −2.42 (−4.04– −0.81) < 0.001
11th 111 1.82 (0.84–2.79) 6.72 −3.69 (−5.38– −1.99) < 0.001
12th 107 2.40 (1.40–3.41) 8.03 −3.10 (−4.83– −1.37) < 0.001
13th 88 1.86 (0.75–2.96) 7.42 −3.65 (−5.51– −1.78) < 0.001
14th 85 1.68 (0.55–2.81) 7.33 −3.83 (−5.72– −1.93) < 0.001
15th 67 1.65 (0.37–2.92) 6.27 −3.86 (−5.95– −1.77) < 0.001
16th 60 2.16 (0.81–3.50) 6.61 −3.35 (−5.53– −1.16) < 0.001
17th 38 0.02 (−1.67–1.72) 5.36 −5.48 (−8.15– −2.81) < 0.001
18th 32 0.24 (−1.58–2.07) 7.18 −5.26 (−8.13– −2.40) < 0.001

*Dunnett’s test.

Abbreviations: ABCr PT, accuracy-based creatinine proficiency testing; CI, confidence interval.

Ann Lab Med 2021;41:372~379 https://doi.org/10.3343/alm.2021.41.4.372

© Ann Lab Med