Evaluation of a particle enhanced turbidimetric assay for the measurement of neutrophil gelatinase-associated lipocalin in plasma and urine on Architect-8000: Analytical performance and establishment of reference values.

OBJECTIVES: Neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker for acute kidney injury. NGAL can be measured in both blood and urine. Apart from kidney injury, NGAL levels in both plasma and urine can be influenced by various pathological situations. Accurate evaluation and comparison of results deriving from clinical studies require robust assays, appropriate specimen handling and reference intervals that will reflect its levels in a healthy population for both biological matrices. METHODS: We report the analytical validation of a latex particle-enhanced turbidimetric immunoassay (PETIA) aimed to measure NGAL in plasma and urine on an automated biochemistry analyzer (ABBOTT-Architect-8000). Assay performance characteristics were evaluated using standard protocols. Urine and plasma specimen storage requirements were determined and reference ranges for blood and urine were determined using healthy controls. RESULTS: The assay is precise (total CV%<4.8%), and sensitive (limit of quantification: 8.4 ng/mL for plasma and 9.0 ng/mL for urine), showing no hook effect. Calibration is stable for at least 30 days. The assay showed excellent linearity over the studied interval (20-4450 ng/mL). The analyte is stable at 4 °C for at least 5 days, and at 20 °C for 4h. Gender specific reference ranges for plasma (male: 38.7-157.6 ng/mL, female: 24.4-142.5 ng/mL) and unisex for urine (<9.0-49.41 ng/mL) are proposed. CONCLUSION: Our data indicate that NGAL can be measured with adequate precision and sensitivity on automated biochemistry analyzers and its measurement could easily be added to a standard panel to screen kidney diseases.

Fondaparinux for the treatment of acute heparin-induced thrombocytopenia: a single-center experience.

Heparin-induced thrombocytopenia (HIT) is a life-threatening immune response to heparin that is associated with a high risk of thromboembolic complications. The syndrome is caused by antibodies that are reactive against complexes of platelet factor 4/heparin (PF4/H). For patients with HIT, the discontinuation of heparin alone is not sufficient and the diagnosis necessitates the administration of an alternative anticoagulant. Fondaparinux is a synthetic pentasaccharide that binds to antithrombin and potentiates inhibition of factor Xa. Data have shown that fondaparinux is structurally too short to induce an antibody response and could be a useful agent to treat HIT. In our hospital, we retrospectively analyzed the use of fondaparinux in the treatment of 24 patients with acute HIT during unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) administration and compared the results to a similar population of 20 patients who were treated with lepirudin. The treated patients had a complete platelet count recovery, and none experienced a new thromboembolic complication or major bleeding. The development of limb gangrene (2 patients who received lepirudin and 1 who received fondaparinux) likely resulted from a delay in diagnosis and treatment initiation. Our data suggest that fondaparinux may be considered a safe and an effective alternative treatment in HIT complicated with or without thrombosis.

VKORC1 and CYP2C9 allelic variants influence acenocoumarol dose requirements in Greek patients.

AIM: To identify the frequencies of the polymorphisms CYP2C9*2, CYP2C9*3 and VKORC1-1639 G>A in the Greek population and investigate whether these polymorphisms and patient demographics (age, sex and comedication) could explain the interindividual variability of acenocoumarol dose requirements for efficient anticoagulation. MATERIALS & METHODS: CYP2C9*2 (Arg144Cys), CYP2C9*3 (Ile359Leu) and VKORC1-1639G>A allelic variants were analyzed in 98 patients treated with acenocoumarol. RESULTS: Allelic frequencies of CYP2C9*2, CYP2C9*3 and VKORC1A were found to be 0.155, 0.075 and 0.485, respectively. Carriership of at least one CYP2C9*3 allele led to the most pronounced reduction in the required mean dose (p<0.0001). In contrast, the CYP2C9*2 allele played a minor role (p=0.3). VKORC1 A/A patients needed approximately a third of the dose required by wild-type patients to achieve the target INR (p<0.0001). Age was the only demographical factor significantly affecting acenocoumarol dose (p<0.0001). In a multivariable regression model, CYP2C9, VKORC1 genotypes and age explained 55% of acenocoumarol dosing variability. CONCLUSION: VKORC1-1639G>A, CYP2C9*2 and CYP2C9*3 polymorphisms were found to predispose to acenocoumarol sensitivity in Greeks. Other hereditary and nongenetic parameters must be incorporated in an individualized dosing algorithm to achieve a safer anticoagulant effect.