TABLE 5.
Comparison of the proportion of the validation cohort with annual changes exceeding the percentage annual change value (ACV) and reference change values (RCV) calculated using assay manufacture‐reported analytical variation
| Analyte | Author | CVi | CVa (manufacturer) | RCV (%) | ACV (%) | Number of validation cohort with increase > RCV | Number of validation cohort with decrease > RCV | Proportion outside RCV (%) | Proportion outside ACV | Significance |
|---|---|---|---|---|---|---|---|---|---|---|
| Glucose (234) | A | 10.7 | 1 | 29.78813 | −26 to 32 | 4 | 3 | 3.0 | 3.4 | 1.0 |
| B | 9.5 | 1 | 26.47814 | 5 | 4 | 3.8 | 3.4 | 1.0 | ||
| Phosphate (234) | A | 12.7 | 2.1 | 35.68061 | −36 to 41 | 4 | 13 | 7.3 | 6.8 | 1.0 |
| BUN (238) | A | 13.1 | 2.5 | 36.96666 | −40 to 49 | 20 | 8 | 11.8 | 9.2 | .03 |
| B | 16.1 | 2.5 | 45.16173 | 17 | 2 | 8.0 | 9.2 | .37 | ||
| Calcium (233) | A | 1.2 | 1.3 | 4.903918 | −9 to 7 | 13 | 32 | 19.3 | 3.9 | <.0001 |
| Creatinine (238) | A | 6.6 | 3.7 | 20.97292 | −28 to 28 | 19 | 12 | 13.0 | 5 | <.0001 |
| B | 14.6 | 3.7 | 41.74846 | 2 | 4 | 2.5 | 5 | .03 | ||
| Cholesterol (234) | A | 5.7 | 1.1 | 16.09111 | −30 to 43 | 34 | 18 | 22.2 | 4.7 | <.0001 |
| B | 7.3 | 1.1 | 20.463 | 24 | 8 | 13.7 | 4.7 | <.0001 | ||
| Albumin (234) | A | 5.8 | 1.5 | 16.60572 | −11 to 14 | 2 | 2 | 1.7 | 5.1 | .007 |
| B | 2.4 | 1.5 | 7.844898 | 24 | 28 | 22.2 | 5.1 | <.0001 | ||
| ALT (238) | A | 19.5 | 3.8 | 55.06798 | −60 to 149 | 15 | 8 | 9.7 | 4.2 | .0002 |
| B | 9.7 | 3.8 | 28.87659 | 24 | 29 | 22.3 | 4.2 | <.0001 | ||
| AST (238) | A | 16.3 | 3.7 | 46.33069 | −47 to 55 | 11 | 7 | 7.6 | 5.0 | .03 |
| B | 11.4 | 3.7 | 33.22186 | 21 | 17 | 16.0 | 5.0 | <.0001 | ||
| ALP (231) | A | 13.4 | 1.5 | 37.37489 | −52 to 74 | 19 | 29 | 20.8 | 7.4 | <.0001 |
| B | 8.6 | 1.5 | 24.19787 | 23 | 74 | 42.0 | 7.4 | <.0001 | ||
| GGT (238) | A | 17.8 | 1.1 | 49.43321 | −66 to 323 | 40 | 17 | 23.9 | 1.3 | <.0001 |
| Total protein (234) | A | 5.3 | 0.8 | 14.85727 | −9 to 16 | 4 | 0 | 1.7 | 3.0 | .25 |
| B | 2.6 | 0.8 | 7.540271 | 29 | 6 | 15.0 | 3.0 | <.0001 | ||
| Potassium (233) | B | 3.3 | 1.1 | 9.641925 | −14 to 13 | 15 | 17 | 13.7 | 3.4 | <.0001 |
| Triglycerides (234) | A | 35.8 | 1.7 | 99.34436 | −50 to 183 | 9 | 0 | 3.8 | 3.8 | 1.0 |
| Total bilirubin (234) | A | 27.5 | 3.3 | 76.77298 | −50 to 100 | 16 | 0 | 6.8 | 1.3 | .002 |
| Total thyroxine (238) | B | 17.0 | 7.4 | 51.39238 | −53 to 183 | 19 | 6 | 10.5 | 1.7 | <.0001 |
Note: Reference change values were calculated from intraindividual coefficient of variation (CVi) reported for dogs in two published sources (A: Ruaux et al, 2012 18 ; B: reported in Jensen & Kjelgaard‐Hansen, 2008 29 ), and a coefficient of variation (CVA) obtained from the manufacturers' datasheet for each assay used in the current study (Supplementary Table 1). The proportion of systemically healthy dogs in the validation cohort with changes exceeding RCV was compared with the proportion exceeding ACV using a McNemar test. After Bonferroni correction, P < .002 was considered significant (bold).