比较两种用于检测犬猫血清总甲状腺素浓度的方法。
Comparison of 2 assays for measuring serum total thyroxine concentration in dogs and cats.
机构信息
Purdue University, College of Veterinary Medicine, West Lafayette, Indiana.
IDEXX Laboratories Inc, Westbrook, Maine.
出版信息
J Vet Intern Med. 2020 Mar;34(2):607-615. doi: 10.1111/jvim.15703. Epub 2020 Feb 3.
BACKGROUND
No gold standard assay for serum total thyroxine (TT4) concentration in small animals exists. The Microgenics DRI TT4 (MTT4) assay is used by most reference laboratories.
HYPOTHESIS/OBJECTIVES: IDEXX Catalyst Total T4 (CTT4) and Immulite 2000 TT4 (ITT4) results will agree with MTT4 results.
ANIMALS
Residual small animal sera were randomized before reanalysis (dogs, CTT4 versus MTT4: n = 176, ITT4 versus MTT4: n = 74; cats, CTT4 versus MTT4: n = 319, ITT4 versus MTT4: n = 79).
METHODS
Validation and method comparison study. Serum TT4 concentration was measured on all analyzers. Pairwise Pearson correlation, cumulative sum linearity test, regression, and Bland-Altman method were performed.
RESULTS
CTT4 versus MTT4 in dogs: constant bias (y-intercept) was 0.10 μg/dL (95% confidence interval [CI], 0.05-0.15), proportional bias (slope) was 0.86 μg/dL (95% CI, 0.83-0.89); in cats, constant bias was 0.13 μg/dL (95% CI, 0.08-0.20) and proportional bias was 1.01 μg/dL (95% CI, 0.98-1.03), but the test for linearity failed. Bland-Altman plots identified increasing disagreement with increasing serum TT4 concentrations. ITT4 versus MTT4 in dogs, constant bias was 0.14 μg/dL (95% CI, 0.04-0.22) and 0.22 μg/dL (95% CI, 0.09-0.33) for cats; proportional bias was 0.76 (95% CI, 0.72-0.80) for dogs and 0.71 (95% CI, 0.69-0.74) for cats.
CONCLUSIONS AND CLINICAL IMPORTANCE
Differences in CTT4 and MTT4 results affect interpretation at higher serum TT4 concentrations. The ITT4 proportional bias will underestimate serum TT4 concentrations in dogs and cats, compared to MTT4. Serial TT4 measurements should be done using the same assay.
背景
目前尚无小动物血清总甲状腺素（TT4）浓度的金标准检测方法。大多数参考实验室使用的是美森尼克 DRI TT4（MTT4）检测法。
假设/目的：IDEXX Catalyst 总 T4（CTT4）和 Immulite 2000 TT4（ITT4）的检测结果将与 MTT4 检测结果一致。
动物
在重新分析之前，将剩余的小动物血清随机分组（狗，CTT4 与 MTT4：n = 176，ITT4 与 MTT4：n = 74；猫，CTT4 与 MTT4：n = 319，ITT4 与 MTT4：n = 79）。
方法
验证和方法比较研究。在所有分析仪上测量血清 TT4 浓度。进行了 Pearson 相关系数、累积和线性检验、回归和 Bland-Altman 方法分析。
结果
狗中 CTT4 与 MTT4 的比较：恒定偏差（y 截距）为 0.10μg/dL（95%置信区间[CI]，0.05-0.15），比例偏差（斜率）为 0.86μg/dL（95%CI，0.83-0.89）；猫中，恒定偏差为 0.13μg/dL（95%CI，0.08-0.20），比例偏差为 1.01μg/dL（95%CI，0.98-1.03），但线性检验失败。Bland-Altman 图显示，随着血清 TT4 浓度的增加，差异逐渐增大。狗中 ITT4 与 MTT4 的比较，恒定偏差为 0.14μg/dL（95%CI，0.04-0.22）和 0.22μg/dL（95%CI，0.09-0.33），猫中为 0.14μg/dL（95%CI，0.04-0.22）和 0.22μg/dL（95%CI，0.09-0.33）；比例偏差为狗中 0.76（95%CI，0.72-0.80）和猫中 0.71（95%CI，0.69-0.74）。
结论和临床意义
CTT4 和 MTT4 检测结果的差异会影响高血清 TT4 浓度的解释。与 MTT4 相比，狗和猫的 ITT4 比例偏差会低估血清 TT4 浓度。应使用相同的检测方法进行 TT4 的连续检测。
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