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Höglund K, Palmqvist H, Ringmark S, Svensson A. Quantification of normetanephrine in canine urine using ELISA: evaluation of factors affecting results. J Vet Diagn Invest 2021; 34:28-35. [PMID: 34697963 PMCID: PMC8689017 DOI: 10.1177/10406387211052984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Catecholamine release increases in dogs with pheochromocytomas and in situations of stress. Although plasma catecholamines degrade rapidly, their metabolites, normetanephrine (NME) and metanephrine (ME), are stable in acidified urine. Our aim was to verify a human urine ELISA kit for the quantification of NME and ME in canine urine and to determine the effects on metabolite stability of sampling time (morning or midday) and day (ordinary or day spent in a clinic). We analyzed 179 urine samples from 17 healthy dogs. For NME, the mean intra-assay CV was 6.0% for all samples and 4.3% for the canine control; inter-assay CVs were 3.3, 3.8, and 12% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 90-101%. For ME, mean intra-assay CV was 6.5% for samples and 9.0% for the canine control; inter-assay CVs were 12.7, 7.2, and 22.5% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 85-89%. Dilution recovery was unsatisfactory for both metabolites. Based on our verification results, NME was selected for remaining analyses. We found no effect on NME concentrations of acidification or room temperature storage for up to 24 h. The NME:creatinine ratio was higher after the first of 3 clinic days compared to the same morning (111.2 ± 5.5 vs. 82.9 ± 5.3; p < 0.0001), but not on the other days. NME verification results were generally superior to ME. Dilution studies were unsatisfactory for both metabolites. Given that NME was stable without acidification at room temperature, urine samples can be collected at home. The clinic environment can cause higher NME:creatinine ratios, especially in unaccustomed dogs.
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Affiliation(s)
- Katja Höglund
- Departments of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Hanna Palmqvist
- Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sara Ringmark
- Departments of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anna Svensson
- Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Srithunyarat T, Svensson A, Hanås S, Höglund OV, Hagman R, Lilliehöök I, Olsson U, Ljungvall I, Häggström J, Ström Holst B, Pettersson A, Höglund K. Evaluation of an ELISA for metanephrines in feline urine. J Vet Diagn Invest 2018; 30:887-893. [PMID: 30136903 DOI: 10.1177/1040638718793168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Catecholamines can be used to evaluate neuroendocrine tumors, stress, and potentially pain, but catecholamines degrade rapidly. Their metabolites normetanephrine (NME) and metanephrine (ME) have better stability in urine. In cats, urine sampling in a home environment would be beneficial to reduce effects of clinical stress and simplify sampling. We evaluated a human urine ELISA for analysis of NME and ME in feline urine, and investigated the effects of acidification, cat tray pellets, and storage time at room temperature up to 8.5 h. In 26 feline urine samples, mean NME concentration was 192 ± 80 ng/mL, mean intra- and inter-assay CV was 6.5% and 4.2%, respectively, and spike recovery was 98-101%, but dilutional recovery was unsatisfactory. For ME, mean intra- and inter-assay CV was 10.2% and 4.1%, respectively. Mean urine ME concentration was 32.1 ± 18.3 ng/mL, close to the kit's lowest standard, and spike recovery was 65-90%; the ELISA could not be validated for ME. The stability study, performed for NME on 12 urine samples, did not identify differences between acidified and non-acidified samples, cat tray pellets, or storage time, and no interaction effects. The ME ELISA was not suitable for feline urine; performance of the NME ELISA was acceptable, except for dilution recovery. For analysis of NME, feline urine can be sampled at home using cat tray pellets and stored at room temperature up to 8.5 h without acidification.
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Affiliation(s)
- Thanikul Srithunyarat
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Department of Surgery and Theriogenology, Khon Kaen University, Khon Kaen, Thailand
| | - Anna Svensson
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sofia Hanås
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Evidensia Animal Clinic, Västerås, Sweden
| | - Odd V Höglund
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ragnvi Hagman
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Inger Lilliehöök
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ulf Olsson
- Unit of Applied Statistics and Mathematics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ingrid Ljungvall
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jens Häggström
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Bodil Ström Holst
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ann Pettersson
- Departments of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Katja Höglund
- Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
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