On Accuracy and Precision of a HPLC Method for Measurement of Urine Porphyrin Concentrations
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Floris M.J. Zuijderhoudt
Abstract
We studied the accuracy and precision of a HPLC method for determination of porphyrins in urine. A commercial standard solution appeared to contain less porphyrins than indicated by the manufacturer, since calibration resulted in lower concentrations of uroporphyrin and coproporphyrin: 16% and 8%, respectively. Coefficients of variation for the measurement of uro-, hepta-, copro I and copro III porphyrins in samples of patients with and without porphyria were often much less than 15%. Comparison of measurements with and without calibrated standards revealed differences for uroporphyrin and coproporphyrin of 27% and 5%, respectively. Recovery of added uroporphyrin and coproporphyrin was 99%. The main cause of the variability in test results was apparently the improperly calibrated standard solutions. The precision of porphyrin measurements was not influenced by the type of porphyria.
Copyright © 2000 by Walter de Gruyter GmbH & Co. KG
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Articles in the same Issue
- Laboratory Diagnosis of Patients with Acute Chest Pain
- Methods for the Determination of Plasma Total Homocysteine: a Review
- Serum Protein 90K/Mac-2BP Is an Independent Predictor of Disease Severity during Hepatitis C Virus Infection
- Interferon β1a Therapy Changes Lipoprotein Metabolism in Patients with Multiple Sclerosis
- On-Line Analysis of Electrolytes in Extracorporeally Circulating Blood: Application of a Rat Model to Examine the Effect of a Single Pharma-cological Dose of Melatonin on Electrolyte Levels in Blood
- Biochemical and Hematological Changes in Low-Level Aluminum Intoxication
- On Accuracy and Precision of a HPLC Method for Measurement of Urine Porphyrin Concentrations
- Human Heart-Type Cytoplasmic Fatty Acid-Binding Protein (H-FABP) for the Diagnosis of Acute Myocardial Infarction. Clinical Evaluation of H-FABP in Comparison with Myoglobin and Creatine Kinase Isoenzyme MB
- Quality Control of Coated Antibodies: New, Rapid Determination of Binding Affinity
- Determination of Reticulocytes: Three Methods Compared
- A New Modular Chemiluminescence Immunoassay Analyser Evaluated
- Point-of-Care Testing
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- Capillary Electrophoresis: Theory and Practice. P. Camilleri, editor
- Life, the Lab, and Everything. Ian Wilkinson
