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Table. 1.

Table. 1.

Summary of optimal lambdas for Box-Cox transformation, lower and upper autoverification limits at 90% clinical specificity, and Z-values and corresponding probabilities (the one-tailed clinical sensitivity was calculated as one-probability) after application of the tolerable total error

Measurands N CVg, % Clinical specificity set as 90%

Optimal lambda 5th percentile (lower autoverification limit) 95th percentile (upper autoverification limit) RCPAQAP APS (tolerable total error, %) Z-value at upper autoverification limit Probability at upper autoverification limit Clinical sensitivity (one-tailed) Clinical sensitivity (two-tailed)
Alanine aminotransferase, IU/L 5,058 29.3 −0.33 10 63 12 1.53 93.7 6.3 12.6
Bicarbonate, mmol/L 4,980 4.4 0.96 23 31 10 0.39 65.2 34.8 69.7
Calcium, mmol/L 4,646 2.7 0.7 2.16 2.44 4 0.61 72.9 27.1 54.2
Chloride, mmol/L 4,980 1.3 2 100 107 3 −0.01 50.0 50.0 100.0
Free thyroxine, pmol/L 4,537 10.7 −0.66 9.4 17.2 12 1.09 86.2 13.8 27.6
γ-Glutamyltransferase, IU/L 4,939 44.5 −0.53 11 85 12 1.55 93.9 6.1 12.1
High-density lipoprotein, mmol/L 5,160 24.5 –0.2 0.86 1.98 12 1.25 89.4 10.6 21.1
Phosphate, mmol/L 4,649 10.7 0.53 0.91 1.39 8 0.94 82.9 17.1 34.2
Potassium, mmol/L 5,065 4.2 –0.08 3.8 4.8 5 0.94 82.6 17.4 34.7
Total protein, g/L 5,026 4.6 0.26 64 78 5 0.85 80.2 19.8 39.5
Triglycerides, mmol/L 5,159 37.1 0.43 0.55 2.91 12 1.45 80.2 19.8 39.5
Urea, mmol/L 5,057 21.0 –0.1 2.8 6.8 12 1.11 86.7 13.4 26.7

Abbreviations: RCPAQAP APS, Royal College of Pathologists Australasia Quality Assurance Programs, analytical performance specifications; CVg, between-subject biological variation (obtained from https://biologicalvariation.eu/).

Ann Lab Med 2022;42:597~601 https://doi.org/10.3343/alm.2022.42.5.597

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