Troponin t hs stat

hs‐cTnT was measured using an automated immunoassay (Troponin T hs STAT, Elecsys‐2010; Roche Diagnostics, Indianapolis, IN).19 Five nanograms per liter represents the limit of detection for this assay. An absolute threshold of ≥14 ng/L is considered abnormal for this assay.20, 21 Assessment of change in troponin over time is recommended to discriminate patients with and without acute cardiomyocyte injury.22, 23 Therefore, we considered patients to have a significant chemotherapy‐induced troponin rise if hs‐cTnT 6 to 24 hours after chemotherapy was at least 5 ng/L greater than the precycle baseline. Patients were categorized into 3 hs‐cTnT categories, those with: acute hs‐cTnT elevations (hs‐cTnT ≥14 ng/L at any time point, plus ≥5 ng/L rise from baseline); chronic elevation (hs‐cTnT >14 ng/L at any time point, but <5 ng/L rise from baseline); or normal (<14 ng/L at all time points).

Serum Na⁺, K⁺, glucose, creatinine, and C-reactive protein (CRP) were determined on hospital admission by standard biochemical methods. Na⁺ at hospital discharge was also included in a subgroup of patients from the derivation cohort with serial Na⁺ measurements. Creatinine clearance was estimated by the Cockcroft-Gault formula [24 (link)]. Arterial blood gas measurements from admission were retrieved from hospital records. Na⁺ concentrations were corrected for the diluting effect of hyperglycemia by the Hillier formula [25 (link)], and hyponatremia was defined as [Na⁺] <137 mmol/L according to the local reference based on the Nordic reference interval project (NORIP).[26 (link)] N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-TnT) were measured in samples obtained <24 h after hospital admission by commercially available assays (proBNP II assay and Troponin T hs STAT, Roche Diagnostics, Penzberg, Germany).

The level of circulating hs-cTnT is obtained using a high-sensitivity and high-precision cardiac troponin assay-Troponin T hs STAT (Roche Diagnostics GmbH Shanghai Co., Ltd, Shanghai, China) by electrochemiluminescence in the Cobas e601(Roche Diagnostics GmbH Shanghai Co., Ltd, Shanghai, China). Circulating hs-cTnT’s normal reference value range stands at 0–14 ng/L, with its lower limit of detection being 3 ng/L [9 (link)].

After 30 min of rest in the supine position, venous blood samples were drawn before HD in lithium-heparin-coated tubes. Samples were centrifuged, and the separated plasma (5 mL) was stored at − 80 °C. Plasma levels of TnT were measured with a previously validated automated Roche high sensitivity TnT immunoassay (Troponin T hs STAT Roche Diagnostics, Mannheim, Germany) on a Cobas e601 analyser according to the instructions of the manufacturer. The assay uses two cardiac TnT-specific mouse monoclonal antibodies in a sandwich format. The antibodies recognize epitopes located in the central part of the TnT molecule (amino acid positions 125–131 and 135–147, respectively). The assay does not exhibit significant cross-reaction with other troponins (skeletal muscle troponin T, cardiac/skeletal troponin I or human troponin C). Detection limit is 5 ng/L with a total imprecision of less than 10% at a level of 13 ng/L, and in 616 healthy volunteers, the upper 99th percentile was 13.5 ng/L [25 (link)]. Analytical within assay coefficient of variation in HD patients is approximately 1.7–6% according to previous studies [26 (link)–28 (link)]. N-terminal pro b-type natriuretic peptide (NT-proBNP) methodology has previously been described in detail [21 (link)].