Page 84 - Exploring the Potential of Self-Monitoring Kidney Function After Transplantation - Céline van Lint

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Chapter 4
Federation of Clinical Chemistry and Laboratory Medicine (EFLM) [21]. For kidney function, one can distinguish between diagnosing and monitoring purposes, recognizing that both may require different levels of robustness as well as different criteria for performance assessment.
The aim of this study was two-fold. First, to assess the suitability of the StatSensor® for detecting current renal function of kidney transplant patients with a single creatinine measurement, by evaluating the metrological traceability and exchangeability of StatSensor® results compared to an isotopic dilution mass spectrometry (IDMS) traceable enzymatic creatinine central laboratory method. Second, to assess the suitability of the StatSensor® for monitoring creatinine trends in kidney transplant patients with serial creatinine measurements, by evaluating the concordance of sequential StatSensor® results to sequential results of the reference laboratory method around the cut-off level used for early identification of kidney rejection in kidney transplant patients.
MATERIALS AND METHODS
Ethics approval
This study was performed at the Leiden University Medical Centre (LUMC). It was part of the pilot study Teletransplant which protocol was approved of by the LUMC Medical Ethics Committee.
Materials
The StatSensor® Xpress-iTM Creatinine Hospital Meter (Nova Biomedical, Waltham, MA, USA) is a handheld point-of-care (POC) device developed for measuring creatinine in capillary (finger prick) whole blood as well as venous and arterial whole blood. Serial numbers of the StatSensor® devices used were 149010610225, 149024910321, 149025210321, 149025910321, 149027410321 and 149027610321. The StatSensor strip technology utilizes a gold-based multiwell, multilayer technology that corrects for the influence of interfering substances that can be present in the whole blood matrix of hospitalized patients. Creatinine is measured enzymatically with signal detection method based on amperometry.
According to the product insert, test results are traceable to National Institute of Standard and Technology (NIST) SRM 967. Two batches of strips with LOT numbers 4910348249 and 4911013249 were used. During the evaluation study, five levels of calibrators were used (n=2) which were analyzed on six different StatSensor® devices with two batches of strips (see Supplemental Data, 1 that accompanies the article http://www.degruyter.com/view/j/cclm.2015.53.issue-10/cclm-2014-