Karl G. Hock

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Measurement of blood concentrations of cystatin C (cysC), a cysteine protease inhibitor present in human plasma, has been suggested for use as an indicator of glomerular filtration rate (GFR) in a manner analogous to the use of plasma creatinine (SCR). In this study, cysC and SCR were measured in plasma from pediatric patients (4-19 years) with renal(More)
and aqueous sample point to possible problems in the measurements of samples with high crosslinks concentrations. The reasons for these inconsistencies need to be investigated in further studies. Commutability issues of the aqueous sample and supplemented pool may be less likely because most assays calibrate with aqueous standards and the modifications of(More)
BACKGROUND Recent guidelines for use of cardiac troponin to detect cardiac damage and for cardiovascular risk stratification have made increasingly sensitive troponin assays important. Troponin assays continue to be plagued by interferences caused by heterophilic antibodies (HAs). We evaluated the performance of a revised cardiac troponin I (cTnI) assay(More)
BACKGROUND Monitoring whole-blood concentrations of cyclosporin A (CsA) is common practice in the management of solid organ and bone marrow transplant recipients. In a multicenter study we evaluated a new, direct (no pretreatment) CsA assay on the Dade Behring Dimension RxL system and compared results with those from the Abbott TDx CsA immunoassay and a(More)
BACKGROUND Plasma concentrations of human chorionic gonadotropin (hCG) have been shown to increase with age due to pituitary secretion. We previously recommended that an hCG cutoff of 14.0IU/L be used for women ≥55years of age. However, it remains unknown whether concentrations >14.0IU/L can be expected in women with advanced age. Our objectives were to(More)
BACKGROUND This study determines the analytical characteristics of the i-STAT cardiac troponin I assay (cTnI; i-STAT, Princeton, NJ), a 10-min POC assay, designed to be performed at the bedside. METHODS Three different hospitals participated in a patient specimen and analytical validation study (n=186) for the i-STAT cTnI assay carried out in real time. A(More)
BACKGROUND Therapeutic drug monitoring for tacrolimus is important for organ transplant patients receiving this immunosuppressant. Current available assays for tacrolimus require sample pre-treatment and operate in a batch mode. Here a no-pretreatment tacrolimus assay, performed on the Dade Behring Dimension analyzer is compared to the Abbott IMx tacrolimus(More)
BACKGROUND Nosocomial pneumonia is a difficult diagnosis to establish in the intensive care unit setting, due to the non-specific nature of the clinical and radiographic findings. Procalcitonin is a circulating biomarker that may become elevated in the presence of bacterial infection. METHODS We conducted a prospective single-center cohort study at(More)
OBJECTIVES To determine the feasibility of laboratories to use an instrument's Hemolytic Index (HI) to determine if a test result would be accurate in the presence of hemoglobin-based oxygen carrier HBOC-201. DESIGN AND METHODS HI values from the Roche Hitachi Modular P800 for samples containing HBOC-201 were determined. HI limits for 24 tests determined(More)
BACKGROUND Galectin-3 (Gal-3) has been suggested as a prognostic biomarker in heart failure (HF) patients that may better reflect disease progression than traditional markers, including B-type natriuretic peptide (BNP) and cardiac troponins. To fully establish the utility of any biomarker in HF, its biologic variability must be characterized. METHODS To(More)