A-374 i-STAT hs-TnI: High sensitivity cardiac troponin at the point of care

Abstract Background The i-STAT hs-TnI cartridge, for use with the i-STAT 1 analyzer, is the first point-of-care, high-sensitivity troponin test to provide lab-quality results at the patient bedside in the United States. The i-STAT hs-TnI test provides precise and accurate cardiac troponin results between 2.9 ng/L and 1000.0 ng/L using whole blood or plasma specimens in approximately 15 minutes. It is demonstrated to be safe and effective to meet the needs of clinicians as a high sensitivity cardiac troponin test to aid in the diagnosis of myocardial infarction. Methods Analytical performance of the i-STAT hs-TnI test in the i-STAT hs-TnI cartridge with the i-STAT 1 analyzer was demonstrated through testing of multi-day precision, linearity, limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), precision in whole blood and plasma, high altitude performance, and evaluation of other factors affecting results (hematocrit insensitivity, potential interfering substances). Performance was also evaluated against the definition of a “high sensitivity” cardiac troponin test as recommended in the Fourth Universal Definition of Myocardial Infarction (Thygesen et al., Circulation 2018). Results Acceptance criteria were met for all analytical performance studies. In the multi-day precision study, the within-laboratory precision (excluding outliers) ranged from 3.30 %CV to 6.61 %CV for sample levels ranging from 11.59 ng/L to 786.65 ng/L. Linearity was demonstrated across the reportable range of the test. The LoB, LoD and LoQ (20 %CV) were established to be 0.78 ng/L, 1.61 ng/L and 2.90 ng/L, respectively, in whole blood, and 0.57 ng/L, 1.05 ng/L and 1.18 ng/L, respectively, in plasma. Within-site precision across both sample types was less than 0.778 ng/L for sample levels below 12.0 ng/L and less than 8.05 %CV for sample levels above 12.0 ng/L. The i-STAT hs-TnI test exhibited acceptable performance up to 10,000 ft above sea level and demonstrated insensitivity to hematocrit levels between 15 %PCV and 55 %PCV. Performance of the i-STAT hs-TnI test was demonstrated to meet the definition of a “high sensitivity” cardiac troponin test. A coefficient of variance of 10% was achieved at 6.88 ng/L and 3.70 ng/L in whole blood and plasma, respectively, which are each below the 99th percentile upper reference limits (URL’s) of 13 ng/L (female), 28 ng/L (male) and 21 ng/L (overall) established in a Reference Range clinical study. Furthermore, greater than 50% of female and greater than 50% of male whole blood and plasma specimens from the apparently healthy (normal) population were detected above the respective LoD value. Conclusion The analytical performance studies demonstrate that the i-STAT hs-TnI cartridge with the i-STAT 1 analyzer offers precise and accurate cardiac troponin test results for safe and effective use at the point of care. The performance of i-STAT hs-TnI test was also shown to meet the definition of a “high sensitivity” cardiac troponin test. The studies were funded by Abbott Laboratories.