Island Medical Program, Faculty of Medicine, University of British Columbia, Victoria, BC, Canada.
Vancouver General Hospital, Vancouver, BC, Canada.
Pediatr Nephrol. 2022 Jun;37(6):1347-1353. doi: 10.1007/s00467-021-05324-0. Epub 2021 Nov 10.
The presence of ketone bodies (KBs) can interfere with creatinine (Cr) measurement in both enzymatic and Jaffe methods. Since a high proportion of children hospitalized for diabetic ketoacidosis (DKA) develop acute kidney injury (AKI), here we investigate whether KB interferences affect the accuracy of pediatric Cr measurement.
Residual patient plasma samples were pooled to make three Cr levels (~ 50, 100, and 250 μM). KBs (acetone, acetoacetate, and β-hydroxybutyrate) were used to spike the pooled samples. All samples were measured for Cr by two enzymatic methods (E1 and E2), two Jaffe methods (J1 and J2), and LC-MS/MS. LC-MS/MS was considered the gold standard, and the % difference in Cr concentration was calculated for each method.
E1 and E2 were unaffected by the presence of all three KBs. J1 and J2 were unaffected by the presence of β-hydroxybutyrate. The presence of acetone resulted in dose-dependent positive interference in both Jaffe methods, whereas the presence of acetoacetate resulted in dose-dependent positive and negative interference in J1 and J2, respectively.
Compared to the enzymatic methods, the Jaffe methods were much more susceptible to interference by acetone and acetoacetate, especially at lower Cr values which are commonly seen in pediatrics. Interpretation of changes in Cr concentration between different hospitals when transferring patients can become ambiguous and true kidney function unclear if different methods are used without awareness of method-specific biases. To improve DKA patient care, we recommend standardizing all of the Cr methods to an enzymatic method. A higher resolution version of the Graphical abstract is available as Supplementary information.
酮体（KBs）的存在会干扰酶法和 Jaffe 法测定肌酐（Cr）。由于因糖尿病酮症酸中毒（DKA）住院的儿童中有很大一部分会发生急性肾损伤（AKI），因此我们在此研究 KBs 干扰是否会影响儿科 Cr 测定的准确性。
将患者剩余的血浆样本混合制成 3 个 Cr 水平（~50、100 和 250 μM）。使用丙酮、乙酰乙酸和β-羟丁酸将 KBs 加入到混合样本中。使用两种酶法（E1 和 E2）、两种 Jaffe 法（J1 和 J2）和 LC-MS/MS 对所有样本进行 Cr 测定。LC-MS/MS 被认为是金标准，计算了每种方法 Cr 浓度的差异百分比。
E1 和 E2 不受三种 KBs 存在的影响。J1 和 J2 不受β-羟丁酸存在的影响。丙酮的存在导致两种 Jaffe 法均产生剂量依赖性的正干扰，而乙酰乙酸的存在导致 J1 和 J2 分别产生剂量依赖性的正干扰和负干扰。
与酶法相比，Jaffe 法更容易受到丙酮和乙酰乙酸的干扰，尤其是在儿科中常见的较低 Cr 值时。如果在不知道方法特异性偏倚的情况下，使用不同的方法，在不同医院之间转移患者时，Cr 浓度变化的解释可能会变得模糊，真正的肾功能也会变得不清楚。为了改善 DKA 患者的治疗，我们建议将所有 Cr 方法标准化为酶法。更详细的图表可在补充信息中查看。
