Critical differences based on biological variation (III)
| Items | Unit | Selected BV and CD | Westgard BV Database [6] | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean | CVI (%) | CVG (%) | CVA (%) | CD (%) | Reference | CVI (%) | CVG (%) | CVA (%) | |||
| AFP | μg/L | 3.9 | 12.4 | 45.1 | 7.1 | 39.6 | [14] | 12.2 | 45.6 | 4.0 | |
| CA125 | kU/L | 12.3 | 9.1 | 10.6 | 2.0 | 25.8 | [15] | 24.7 | 54.6 | 8.2 | |
| CA15-3 | U/L | - | 6.2 | 62.9 | 11.2 | 35.5 | [16] | 6.1 | 62.9 | 2.0 | |
| CA19-9 | U/mL | 5.1 | 27.2 | 64.2 | 5.4 | 76.8 | [17] | 16.0 | 130.5 | 5.3 | |
| CEA | μg/L | 1.014 | 30.9 | 37.1 | 3.8 | 86.2 | [17] | 12.7 | 55.6 | 4.2 | |
| PSA, total | μg/L | 0.85 | 6.8 | 42.0 | 3.3 | 20.9 | [18] | 18.1 | 72.4 | 6.0 | |
| Free PSA | μg/L | 0.32 | 7.1 | 46.2 | 1.4 | 20.0 | [18] | - | - | - | |
| T3 | nmol/µg | 2.31 | 6.6 | 17.2 | - | 18.3 | [19] | 6.9 | 12.3 | 2.3 | |
| T4 | mmol/L | 133 | 14.5 | 3.0 | 6.2 | 43.7 | [20] | 4.9 | 10.9 | 1.6 | |
| Free T4 | pmol/L | 18.1 | 9.1 | 14.0 | 5.1 | 28.9 | [20] | 5.7 | 12.1 | 1.9 | |
| Thyroglobulin | μg/L | 5.1 | 16.2 | 128.0 | 2.9 | 45.6 | [21] | 14.0 | 39.0 | 4.6 | |
| TSH | mIU/L | 2.19 | 28.0 | 61.9 | 4.4 | 78.5 | [20] | 19.3 | 24.6 | 6.4 | |
| Estradiol | pmol/L | - | 15.0 | 13.0 | 8.0 | 47.1 | [22] | 22.5 | 24.4 | 7.4 | |
| FSH | IU/L | - | 11.0 | 49.0 | 3.0 | 31.6 | [22] | 11.0 | 47.2 | 3.6 | |
| LH | IU/L | - | 22.0 | 27.0 | 3.0 | 61.5 | [22] | 23.0 | 27.4 | 7.6 | |
| Testosterone | ng/dL | 11.9 | 18.7 | 33.6 | 6.0 | 54.4 | [23] | 9.3 | 22.1 | 3.1 | |
| Prolactin | mIU/L | 136 | 23.0 | 27.0 | 2.8 | 64.2 | [24] | 23.0 | 35.0 | 7.6 | |
Abbreviations: BV, biological variation; CD, critical difference; CVI, within-subject biological coefficient of variation; CVG, between-subject biological coefficient of variation; CVA, analytical coefficient of variation; AFP, alpha-fetoprotein; CA, cancer antigen; CEA, carcinoembryonic antigen; PSA, prostate-specific antigen; T3, tri-iodothyronine; T4, thyroxine; TSH, thyroid-stimulating hormone; FSH, follicle-stimulating hormone; LH, luteinizing hormone