1. Stability of porphyrins and porphyrin precursors in urine and plasma samples: implications for sample handling and storage.
- Author
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Gallagher CJ, Bentley LA, Challenger R, Jones M, and Schulenburg-Brand D
- Subjects
- Humans, Light, Time Factors, Porphyrias diagnosis, Porphyrias urine, Aminolevulinic Acid urine, Porphobilinogen urine, Porphobilinogen blood, Reproducibility of Results, Urinalysis methods, Specimen Handling methods, Porphyrins urine, Porphyrins chemistry, Porphyrins blood, Temperature
- Abstract
The porphyrias are rare disorders of haem biosynthesis. Diagnosis requires demonstrating increased porphyrins or porphyrin precursors in blood, urine and faeces. Patients may only be investigated once, and therefore, understanding the preanalytical factors affecting the reliability of results is crucial. Guidance for sample handling exists, but published evidence regarding the stability of porphyrins and their precursors is limited. The aim of this study was to evaluate the effect of light exposure and different storage temperatures on analyte stability for measurement of urinary aminolaevulinic acid and porphobilinogen, total urine porphyrin and plasma porphyrin. Our results confirm that all samples should be protected from light. Results from samples exposed to light for greater than 4 hours should be interpreted with caution and repeat samples requested. If transported to a specialist laboratory, samples should be stored at 4°C before transport. Transit time at ambient temperatures should be less than 24 hours., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2024
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