FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / BMC Vet Res / Acidification is required for calcium and magnesium concentr...
BMC veterinary research2024; 20(1); 21; doi: 10.1186/s12917-023-03848-1

Acidification is required for calcium and magnesium concentration measurements in equine urine.

Abstract: 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, FE and FE. 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 FE 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 FE 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.
© 2024. The Author(s).
Get Full Text
Publication Date: 2024-01-10 PubMed ID: 38200552PubMed Central: 8996324DOI: 10.1186/s12917-023-03848-1Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research reveals that acidification improves the accuracy of measuring calcium and magnesium concentrations in horse urine. A one-hour waiting period after acidification does not significantly alter these concentrations.

Objective of the Research

  • The main purpose of the study was to examine how acidification and storage time after acidification affects the levels of calcium (Ca), magnesium (Mg), and phosphate (P) in equine urine. In addition, the study also assessed changes in the fractional excretion (FE) of these electrolytes.

Methodology

  • Thirty-two fresh equine urine samples were analyzed between December 2016 and July 2020.
  • A complete urinalysis was carried out on all samples to evaluate their overall health and urine composition.
  • The concentrations of Ca, Mg, P, and creatinine, a waste product of muscle metabolism, were measured in the urine samples after centrifugation. The process was carried out in three scenarios – centrifugation of native urine, centrifugation immediately after urine acidification, and centrifugation an hour post acidification.
  • The urine was acidified using hydrochloric acid to achieve a pH of 1-2.
  • The same concentrations were also measured in blood plasma. Following these measurements, the researchers calculated the fractional excretion of each electrolyte for comparative purposes.
  • The researchers used the Friedman tests to check the equality of medians and Bland-Altman bias plots to evaluate the agreement among different conditions.

Findings

  • The results showed a statistically significant effect of acidification on the concentrations and fractional excretions of calcium and magnesium.
  • A strong positive bias was observed between calcium concentrations in native (unmodified) and acidified urine. The mean bias for this was 17.6 mmol/l.
  • Magnesium concentrations showed a smaller difference between native and acidified urine with a mean bias of 1.8 mmol/l.
  • The study noted that the increase in fractional excretion was clinically meaningful.
  • Storage of acidified urine showed no effect on ion concentrations, meaning there is no need to immediately measure these concentrations post-acidification.
  • Phosphate concentrations in native urine samples were below the detection limit of the assay used. Therefore, the researchers could not conduct statistical analysis or compute the fractional excretion for phosphates.

Conclusion

  • The research concluded that acidifying horse urine is a crucial step for accurately measuring the calcium and magnesium concentrations.
  • This also aids in the computation of the fractional excretion of these electrolytes.
  • Additionally, the storage time of one hour post-acidification does not significantly change the concentrations of these electrolytes in the urine.

Cite This Article

APA
Lapsina S, Stirn M, Hofmann-Lehmann R, Schoster A, Riond B. (2024). Acidification is required for calcium and magnesium concentration measurements in equine urine. BMC Vet Res, 20(1), 21. https://doi.org/10.1186/s12917-023-03848-1

Publication

BMC veterinary research
ISSN: 1746-6148
NlmUniqueID: 101249759
Country: England
Language: English
Volume: 20
Issue: 1
Pages: 21

Researcher Affiliations

Lapsina, Sandra
  • Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Stirn, Martina
  • Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Hofmann-Lehmann, Regina
  • Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Schoster, Angelika
  • Clinic for Equine Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Riond, Barbara
  • Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. briond@vetclinics.uzh.ch.

MeSH Terms

  • Animals
  • Horses
  • Calcium
  • Magnesium
  • Creatinine
  • Body Fluids
  • Hydrogen-Ion Concentration

References

This article includes 30 references
  1. McGowan C. Clinical pathology in the racing horse: the role of clinical pathology in assessing fitness and performance in the racehorse.. Vet Clin N Am Equine Pract 2008;24(2):405–21.
    doi: 10.1016/j.cveq.2008.03.001google scholar: lookup
  2. McKenzie EC. 42 - hematology and serum biochemistry of the equine athlete.. Equine sports medicine and surgery 2014;p. 921–9.
    doi: 10.1016/B978-0-7020-4771-8.00042-9google scholar: lookup
  3. Avioli LV. Intestinal absorption of calcium.. Arch Intern Med 1972;129(2):345–55.
    doi: 10.1001/archinte.1972.00320020189016pubmed: 4258092google scholar: lookup
  4. Tryfonidou MA, van den Broek J, van den Brom WE, Hazewinkel HA. Intestinal calcium absorption in growing dogs is influenced by calcium intake and age but not by growth rate.. J Nutr 2002;132(11):3363–8.
    doi: 10.1093/jn/132.11.3363pubmed: 12421852google scholar: lookup
  5. Hyde ML, Wilkens MR, Fraser DR. In vivo measurement of strontium absorption from the rumen of dairy cows as an index of calcium absorption capacity.. J Dairy Sci 2019;102(6):5699–705.
    doi: 10.3168/jds.2018-16052pubmed: 31005315google scholar: lookup
  6. Wilkens MR, Marholt L, Eigendorf N, Muscher-Banse AS, Feige K, Schroder B, Breves G, Cehak A. Trans- and paracellular calcium transport along the small and large intestine in horses.. Comp Biochem Physiol A Mol Integr Physiol 2017;204:157–63.
    doi: 10.1016/j.cbpa.2016.11.020pubmed: 27915149google scholar: lookup
  7. Caple IW, Doake PA, Ellis PG. Assessment of the calcium and phosphorus-nutrition in horses by analysis of urine.. Aust Vet J 1982;58(4):125–31.
    doi: 10.1111/j.1751-0813.1982.tb00621.xpubmed: 7126061google scholar: lookup
  8. Mair TS, Osborn RS. Crystalline composition of equine urinary calculi.. Res Vet Sci 1986;40(3):288–91.
    doi: 10.1016/S0034-5288(18)30536-8pubmed: 3738224google scholar: lookup
  9. Wood T, Weckman TJ, Henry PA, Chang SL, Blake JW, Tobin T. Equine urine pH: normal population distributions and methods of acidification.. Equine Vet J 1990;22(2):118–21.
    doi: 10.1111/j.2042-3306.1990.tb04222.xpubmed: 2318175google scholar: lookup
  10. King C. Practical use of urinary fractional excretion.. J Equine Vet Sci 1994;14(9):464–8.
    doi: 10.1016/S0737-0806(06)81968-4google scholar: lookup
  11. Gray J, Harris P, Snow DH. Preliminary investigations into the calcium and magnesium status of the horse.. Anim Clin Biochem Future 1988:307–17.
  12. Morris DD, Divers TJ, Whitlock RH. Renal clearance and fractional excretion of electrolytes over a 24-hour period in horses.. Am J Vet Res 1984;45(11):2431–5.
    pubmed: 6524740
  13. Harris PA. Preliminary investigations into factors that affect plasma aldosterone concentrations in horses.. Res Vet Sci 1993;54(3):319–28.
    doi: 10.1016/0034-5288(93)90129-4pubmed: 8337480google scholar: lookup
  14. Harris P, Colles C. The use of creatinine clearance ratios in the prevention of equine rhabdomyolysis: a report of four cases.. Equine Vet J 1988;20(6):459–63.
    doi: 10.1111/j.2042-3306.1988.tb01575.xpubmed: 3215174google scholar: lookup
  15. Coffman J. Percent creatinine clearance ratios.. Vet Med Small Anim Clin 1980;75(4):671–6.
    pubmed: 6900459
  16. Ronen N, van Heerden J, van Amstel SR. Clinical and biochemistry findings, and parathyroid hormone concentrations in three horses with secondary hyperparathyroidism.. J S Afr Vet Assoc 1992;63(3):134–6.
    pubmed: 1404225
  17. Traver DS, Coffman JR, Moore JN, Salem CA. Urine clearance ratios as a diagnostic aid in equine metabolic disease.. Proc Am Assoc Equine Pract 1976;22:177–83.
  18. Hodgkinson A. Sampling errors in the determination of urine calcium and oxalate: solubility of calcium oxalate in HCl-urine mixtures.. Clin Chim Acta 1981;109(2):239–44.
    doi: 10.1016/0009-8981(81)90341-7pubmed: 7471500google scholar: lookup
  19. 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.
    doi: 10.1016/j.cca.2013.08.025pubmed: 24012827google scholar: lookup
  20. 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 2012;50(2):375–7.
    doi: 10.1515/cclm.2011.711google scholar: lookup
  21. Sodi R, Bailey LB, Glaysher J, Allars L, Roberts NB, Marks EM, Fraser WD. Acidification and urine calcium: is it a preanalytical necessity?. Ann Clin Biochem 2009;46:484–7.
    doi: 10.1258/acb.2009.009027pubmed: 19729500google scholar: lookup
  22. Sodi R, Godber IM. Effect of refrigeration, centrifugation, acidification, heat treatment and storage on urine calcium, magnesium and phosphate.. Clin Chem Lab Med 2016;54(12):E379–81.
    doi: 10.1515/cclm-2016-0064pubmed: 27155007google scholar: lookup
  23. Nicar MJ, Hsu MC, Johnson T, Pak CY. The preservation of urine samples for determination of renal stone risk factors.. Lab Med 1987;18(6):382–4.
    doi: 10.1093/labmed/18.6.382pubmed: 11539109google scholar: lookup
  24. Salek T, Musil P, Psencik M, Palicka V. Post-collection acidification of spot urine sample is not needed before measurement of electrolytes.. Biochem Med (Zagreb) 2022;32(2):020702.
    doi: 10.11613/BM.2022.020702pubmed: 35464747pmc: 8996324google scholar: lookup
  25. Walton RM, Cowell RL, Valenciano AC. Equine hematology, cytology, and clinical chemistry.. 2020.
  26. de Moel PJ, van der Helm AWC, van Rijn M, van Dijk JC, van der Meer WGJ. Assessment of calculation methods for calcium carbonate saturation in drinking water for DIN 38404-10 compliance.. Drink Water Eng Sci 2013;6(2):115–24.
    doi: 10.5194/dwes-6-115-2013google scholar: lookup
  27. Baumann JM, Affolter B. From crystalluria to kidney stones, some physicochemical aspects of calcium nephrolithiasis.. World J Nephrol 2014;3(4):256–67.
    doi: 10.5527/wjn.v3.i4.256pubmed: 25374820pmc: 4220359google scholar: lookup
  28. Tiselius HG, Fornander A, Nilsson M. Studies on the crystallization process following addition of calcium phosphate crystals to solutions with a composition corresponding to that in the collecting duct.. Conference proceedings 1999.
  29. Espinosa-Ortiz EJ, Eisner BH, Lange D, Gerlach R. Current insights into the mechanisms and management of infection stones.. Nat Rev Urol 2019;16(1):35–53.
    doi: 10.1038/s41585-018-0120-zpubmed: 30470787google scholar: lookup
  30. Coffman J. Clinical chemistry and pathophysiology of horses percent creatinine clearance ratios.. Vet Med Small Anim Clin 1980:671–6.

Citations

This article has been cited 0 times.
Subscribe to our newsletter
Join 99,357 horse owners like you who receive our email updates on horse health and nutrition.