1
|
Lapsina S, Stirn M, Hofmann-Lehmann R, Schoster A, Riond B. Acidification is required for calcium and magnesium concentration measurements in equine urine. BMC Vet Res 2024; 20:21. [PMID: 38200552 PMCID: PMC10777620 DOI: 10.1186/s12917-023-03848-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 12/05/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Acidification of equine urine to promote dissociation of ion complexes is a common practice for urine ion concentration measurements. The objective of this study was to evaluate the effect of acidification and storage after acidification on calcium (Ca), magnesium (Mg) and phosphate (P) concentrations and on fractional excretion (FE) of these electrolytes. Thirty-two fresh equine urine samples were analysed between December 2016 and July 2020. Complete urinalysis (stick and sediment) was performed on all samples. Ca, Mg, P and creatinine concentrations were measured in supernatant of centrifuged native urine, urine directly centrifuged after acidification and urine centrifuged 1 hour after acidification. Urine was acidified with hydrochloric acid to reach a pH of 1-2. Ca, Mg, P and creatinine concentrations were also measured in blood plasma, and fractional excretion of each electrolyte was calculated. Equality of medians was tested with Friedman tests and Bland-Altman bias plots were used to show the agreement between conditions. RESULTS Acidification had a statistically significant effect on Ca and Mg concentrations, FECa and FEMg. Bland-Altman plot revealed a strong positive proportional bias between Ca concentration in native and acidified urine with a mean bias of 17.6 mmol/l. For Mg concentration, the difference between native and acidified urine was small with a mean bias of 1.8 mmol/l. The increase in FECa was clinically relevant. Storage of acidified urine had no effect on any of the measured ion concentrations. All P concentrations in native urine samples were below the detection limit of the assay and statistical analysis and calculation of FEP was not possible. CONCLUSIONS Urine acidification is essential for accurate measurement of Ca and Mg concentrations and therefore FE calculations in equine urine. Storage time of 1 hour after acidification does not significantly change Ca and Mg concentrations.
Collapse
Affiliation(s)
- Sandra Lapsina
- Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Martina Stirn
- Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Regina Hofmann-Lehmann
- Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Angelika Schoster
- Clinic for Equine Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Barbara Riond
- Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| |
Collapse
|
2
|
Bal C, Topcuoğlu C, Rıfat Balık A, Yılmaz FM, Erel Ö, Yılmaz G. The effect of acid use as a preservative on the results of biochemical tests measured in 24-h urine. Scand J Clin Lab Invest 2022; 82:329-333. [PMID: 35791842 DOI: 10.1080/00365513.2022.2092899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Twenty-four-hour urine measurements play a crucial role in the diagnosis, follow-up and treatment of various diseases. There are different approaches to the collection of urine in patients who need to collect multiple urine samples at a time, especially in hospitals with heavy workloads. In this study, we compared the sodium, potassium, chloride, amylase, calcium, creatinine, phosphorus, microalbumin, protein, magnesium, urea, uric acid, adrenaline, noradrenaline, dopamine, metanephrine, normetanephrine, vanillylmandelic acid, 5-hydroxyindoleacetic acid and homovanillic acid results of 24-h urine samples analyzed immediately without acid addition, which we accepted as the reference and baseline measurement, with the results of the samples analyzed after waiting for 24 h without acid addition, analyzed immediately with acid addition and analyzed after waiting for 24 h with acid addition. Chloride, microalbumin, amylase and protein tests, which are recommended to be measured in the sample without preservatives, are affected by acid addition. Adrenaline, noradrenaline and dopamine, which are the tests recommended to be measured in acid-added urine are degraded in the samples without acid, and the levels of metanephrine and normetanephrine were not significantly degraded in the absence of preservatives.
Collapse
Affiliation(s)
- Ceylan Bal
- Department of Medical Biochemistry, Ankara Yıldırım Beyazıt University, Ankara, Turkey.,Department of Medical Biochemistry, Ankara City Hospital, Ankara, Turkey
| | - Canan Topcuoğlu
- Department of Medical Biochemistry, Ankara City Hospital, Ankara, Turkey
| | - Ahmet Rıfat Balık
- Department of Medical Biochemistry, Gulhane Training and Research Hospital, Ankara, Turkey
| | - Fatma Meriç Yılmaz
- Department of Medical Biochemistry, Ankara Yıldırım Beyazıt University, Ankara, Turkey.,Department of Medical Biochemistry, Ankara City Hospital, Ankara, Turkey
| | - Özcan Erel
- Department of Medical Biochemistry, Ankara Yıldırım Beyazıt University, Ankara, Turkey.,Department of Medical Biochemistry, Ankara City Hospital, Ankara, Turkey
| | - Gülsen Yılmaz
- Department of Medical Biochemistry, Ankara Yıldırım Beyazıt University, Ankara, Turkey.,Department of Medical Biochemistry, Ankara City Hospital, Ankara, Turkey
| |
Collapse
|
3
|
Cadamuro J, Decho C, Frans G, Auer S, von Meyer A, Kniewallner KM, Drerup M, Heinrich E, Keppel MH, Mrazek C, Felder TK, Oberkofler H, Haschke-Becher E, Kipman U, Salek T, Vermeersch P. Acidification of 24-hour urine in urolithiasis risk testing: An obsolete relic? Clin Chim Acta 2022; 532:1-9. [PMID: 35597305 DOI: 10.1016/j.cca.2022.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/09/2022] [Accepted: 05/09/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Recommendations on the optimal preservation of 24 h urine for the metabolic work-up in urolithiasis patients are very heterogeneous. In case two such tests with different storage condition recommendations are being analysed, multiple collections would be needed, challenging especially elderly and very young patients. We therefore aimed to evaluate the stability of urine constituents under different storage conditions. MATERIAL AND METHODS We collected urine samples from ten healthy volunteers and prepared aliquots to be stored either at room temperature or 4 °C. Some aliquots were preserved using hydrochloric acid prior to storage, some thereafter, some using the BD Urine preservation tube and some were not preserved at all. Storage duration was 0, 24, 48 or 72 h. In all samples calcium, magnesium, phosphorus, creatinine, oxalate, citrate and uric acid were measured and compared to the according reference sample. RESULTS We could not find any significant deviation for any of the analytes and preanalytical treatment conditions compared to the associated reference sample. CONCLUSION Preservation of 24 h urine for the metabolic evaluation in stone formers might not be necessary for sample storage up to 72 h.
Collapse
Affiliation(s)
- Janne Cadamuro
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria.
| | - Cosima Decho
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Glynis Frans
- Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Simon Auer
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Alexander von Meyer
- Institute for Laboratory Medicine and Medical Microbiology, Medizet, München-Klinik, Munich, Germany
| | - Kathrin M Kniewallner
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TreCS), Paracelsus Medical University, Salzburg, Austria
| | - Martin Drerup
- Department of Urology, Barmherzige Brüder Hospital, Salzburg, Austria
| | - Elmar Heinrich
- Department of Urology, Barmherzige Brüder Hospital, Salzburg, Austria
| | - Martin H Keppel
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Cornelia Mrazek
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Thomas K Felder
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Hannes Oberkofler
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | | | | | - Tomas Salek
- Department of Clinical Biochemistry and Pharmacology, The Tomas Bata Hospital in Zlín, Havlíčkovo nábřeží 600, 76275 Zlín, The Czech Republic
| | - Pieter Vermeersch
- Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium; Department of Cardiovascular Sciences, KU Leuven, Leuven Belgium
| | | |
Collapse
|
4
|
Chenevier-Gobeaux C, Rogier M, Dridi-Brahimi I, Koumakis E, Cormier C, Borderie D. Pre-, post- or no acidification of urine samples for calcium analysis: does it matter? Clin Chem Lab Med 2019; 58:33-39. [PMID: 31539348 DOI: 10.1515/cclm-2019-0606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/28/2019] [Indexed: 11/15/2022]
Abstract
Background Measuring 24 h-urine calcium concentration is essential to evaluate calcium metabolism and excretion. Manufacturers recommend acidifying the urine before a measurement to ensure calcium solubility, but the literature offers controversial information on this pre-analytical treatment. The objectives of the study were (1) to compare pre-acidification (during urine collection) versus post-acidification (in the laboratory), and (2) to evaluate the impact of acidification on urinary calcium measurements in a large cohort. Methods We evaluated the effects of pre- and post-acidification on 24-h urine samples collected from 10 healthy volunteers. We further studied the impact of acidification on the calcium results for 567 urine samples from routine laboratory practice, including 46 hypercalciuria (≥7.5 mmol/24 h) samples. Results Calciuria values in healthy volunteers ranged from 0.6 to 12.5 mmol/24 h, and no statistical significance was found between non-acidified, pre-acidified and post-acidified conditions. A comparison of the values (ranging from 0.21 to 29.32 mmol/L) for 567 urine samples before and after acidification indicated 25 samples (4.4%) with analytical differences outside limits of acceptance. The bias observed for these deviant values ranged from -3.07 to 1.32 mmol/L; no patient was re-classified as hypercalciuric after acidification, and three patients with hypercalciuria were classified as normocalciuric after acidification. These three deviant patients represent 6.5% of hypercalciuric patients. Conclusions Our results indicate that pre- and post-acidification of urine is not necessary prior to routine calcium analysis.
Collapse
Affiliation(s)
- Camille Chenevier-Gobeaux
- Service de Diagnostic Biologique Automatisé (SDBA), Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), 27 rue du Faubourg Saint-Jacques, 75679 Paris cedex 14, France.,Service de Rhumatologie, Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), Paris, France
| | - Marie Rogier
- Service de Diagnostic Biologique Automatisé (SDBA), Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), Paris cedex 14, France
| | - Imane Dridi-Brahimi
- Service de Diagnostic Biologique Automatisé (SDBA), Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), Paris cedex 14, France
| | - Eugénie Koumakis
- Service de Rhumatologie, Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), Paris, France
| | - Catherine Cormier
- Service de Rhumatologie, Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), Paris, France
| | - Didier Borderie
- Service de Diagnostic Biologique Automatisé (SDBA), Hôpital Cochin, Hôpitaux Universitaires Paris Centre (HUPC), Paris cedex 14, France.,UMR 1124, Université Paris Descartes, Paris, France
| |
Collapse
|
5
|
Sodi R, Godber IM. Effect of refrigeration, centrifugation, acidification, heat treatment and storage on urine calcium, magnesium and phosphate. ACTA ACUST UNITED AC 2016; 54:e379-e381. [DOI: 10.1515/cclm-2016-0064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 03/28/2016] [Indexed: 11/15/2022]
|
6
|
Pratumvinit B, Reesukumal K, Wongkrajang P, Khejonnit V, Klinbua C, Dangneawnoi W. Should acidification of urine be performed before the analysis of calcium, phosphate and magnesium in the presence of crystals? Clin Chim Acta 2013; 426:46-50. [PMID: 24012827 DOI: 10.1016/j.cca.2013.08.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/21/2013] [Accepted: 08/29/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Acidification of urine has been recommended before testing for calcium, phosphate, and magnesium. We investigated the necessity of pre-analytical acidification in both crystallized and non-crystallized urine samples. METHODS From 130 urine samples obtained via routine urine analysis, 65 (50%) samples were classified as non-crystallized. All samples were divided into three groups: untreated samples, acidified samples with HCl, and acidified samples after 1h room-temperature incubation. Urine samples were measured for calcium, phosphate, magnesium, and creatinine using Modular P800 and were examined for crystals using light microscopy. RESULTS In crystallized samples, acidified samples with 1h incubation had significantly higher Ca/Cr, P/Cr, and Mg/Cr than did untreated samples with mean differences of 0.04, 0.03, and 0.01 mg/mg, respectively (P<0.001). In acidified samples that were analyzed immediately, crystallized samples had lower calcium concentrations than those of acidified samples with 1h incubation and a mean difference of 0.21 mg/dl (P = 0.025). None of the sample differences which exceeded the critical difference of urinary Ca, P and Mg was observed. CONCLUSIONS Acidification of urine should be performed before the measurement of Ca, P, and Mg in the presence of urinary crystals. However, the lack of an acidification process does not result in a clinically significant change.
Collapse
Affiliation(s)
- Busadee Pratumvinit
- Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
| | | | | | | | | | | |
Collapse
|
7
|
van Gammeren AJ, van Haperen C, Kuypers AWHM. The effect of acidification and oxalate concentration on urine calcium measurements in EQAS materials and patient samples. Clin Chem Lab Med 2011; 50:375-7. [PMID: 21923474 DOI: 10.1515/cclm.2011.711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Indexed: 11/15/2022]
Abstract
BACKGROUND An increase in urine calcium compared to the consensus value was observed in some urine samples of the Dutch External Quality Assessment Scheme (EQAS). It appeared that the increase was due to the addition of oxalate by the EQAS organizers and preanalytical acidification of the samples by some of the participants. Because of this observation, the effect of urine acidification on urine calcium level in EQAS and patient samples with added oxalate was investigated. METHODS Twenty-four EQAS urine samples and 20 patient urine samples were subject to recovery measurements of urine calcium before and after addition of sodium oxalate and acidification. RESULTS Differences in urine calcium between acidified and non-acidified samples up to 30.9% have been observed in EQAS samples with added oxalate. Patient samples show differences up to 80%. Differences between acidified and non-acidified samples are minimal for low calcium oxalate levels but increase with higher levels. Samples without added oxalate show equal urine calcium results between acidified and non-acidified samples. CONCLUSIONS Urine calcium results are decreased in non-acidified samples with an excess of oxalate. In case of hyperoxaluria, acidification of patient urine collections and EQAS samples is recommended for correct urine calcium values.
Collapse
Affiliation(s)
- Adriaan J van Gammeren
- Department of Clinical Chemistry and Haematology, Amphia Hospital, Breda, The Netherlands.
| | | | | |
Collapse
|
8
|
|
9
|
|