Indian Journal of Critical Care Medicine

Register      Login



Volume / Issue

Online First

Related articles

VOLUME 28 , ISSUE 5 ( May, 2024 ) > List of Articles

Original Article

A Retrospective Database Analysis to Investigate if Electrolytes in Venous Blood are Equivalent to the Levels in Arterial Blood

RN Devaki, Prajna Kasargod, AN Roopa Urs, N Chandrika

Keywords : Chloride, Laboratory research, Potassium, Sodium, Turnaround time

Citation Information : Devaki R, Kasargod P, Urs AR, Chandrika N. A Retrospective Database Analysis to Investigate if Electrolytes in Venous Blood are Equivalent to the Levels in Arterial Blood. Indian J Crit Care Med 2024; 28 (5):442-446.

DOI: 10.5005/jp-journals-10071-24702

License: CC BY-NC 4.0

Published Online: 30-04-2024

Copyright Statement:  Copyright © 2024; The Author(s).


Background: In a critically ill patient, when an arterial blood sample is processed on an arterial blood gas (ABG) analyzer, it also measures electrolytes apart from analyzing the blood gases. The turnaround time for ABG analysis is way too less compared to the conventional electrolyte analysis with a serum sample. Objective: This study intends to investigate whether values of electrolytes estimated in arterial blood can substitute the routinely practiced method. Materials and methods: This is a retrospective cross-sectional study. The source of data is patients’ reports of serum electrolytes and ABG analysis from the Clinical Biochemistry laboratory, CIMS Teaching Hospital, Chamarajanagar between January and June 2021. The electrolytes report of 200 patients from whom both arterial and venous blood samples were sent to the Clinical Biochemistry laboratory on the same day and at the same time for analysis were selected. The data was compiled, compared, and correlated using a suitable statistical tool. Results: The mean and standard deviation of sodium (135.62 ± 5.20 in venous vs 134.08 ± 8.49 in arterial blood), potassium (4.20 ± 0.64 vs 3.80 ± 0.75), and chloride (102.28 ± 4.99 vs 96.33 ± 8.11) were observed. However, when the concordance correlation coefficient and Bland-Altman plot analysis were made there was no agreement between electrolytes analyzed on serum in an autoanalyzer with that of ABG analyzer. Conclusion: We conclude that the electrolytes measured by a conventional autoanalyzer on a serum sample cannot be replaced by values analyzed on a blood gas analyzer.

PDF Share
  1. Andreev M, de Pablo JJ, Chremos A, Douglas JF. Influence of ion solvation on the properties of electrolyte solutions. J Phys Chem B 2018;122(14):4029–4034. DOI: 10.1021/acs.jpcb.8b00518.
  2. Shrimanker I, Bhattarai S. Electrolytes. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2024. Available from:
  3. Schiefermeier-Mach N, Egg S, Erler J, Hasenegger V, Rust P, König J, et al. Electrolyte intake and major food sources of sodium, potassium, calcium and magnesium among a population in western Austria. Nutrients 2020;12(7):1956. DOI: 10.3390/nu12071956.
  4. Dervishi A. A deep learning backcasting approach to the electrolyte, metabolite, and acid-base parameters that predict risk in ICU patients. PLoS One 2020;15(12): e0242878. DOI: 10.1371/journal.pone. 0242878.
  5. Burnett RW, Covington AK, Fogh-Andersen N, Külpmann WR, Lewenstam A, Maas AH, et al. Recommendations for measurement of and conventions for reporting sodium and potassium by ion-selective electrodes in undiluted serum, plasma or whole blood. International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). IFCC Scientific Division Working Group on Selective Electrodes. Clin Chem Lab Med 2000;38(10):1065–1071. DOI: 10.1515/CCLM.2000.159.
  6. Lopez J. Carl A Burtis, Edward R Ashwood, David E Bruns (Eds): Tietz Textbook of Clinical Chemistry and Molecular Diagnosis, 5th edition. St. Louis, USA: Elsevier; 2012, p. 2238. Indian J Clin Biochem 2013;28(1):104–105. DOI: 10.1007/s12291-012-0287-7.
  7. Castro D, Patil SM, Zubair M, Keenaghan M. Arterial Blood Gas. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2024; Available from:
  8. Yi HC, Shi WS, Zhang YH, Zhu XZ, Yu Y, Wang XX, et al. Comparison of electrolyte and glucose levels measured by a blood gas analyzer and an automated biochemistry analyzer among hospitalized patients. J Clin Lab Anal 2020;34(7):e23291. DOI: 10.1002/jcla.23291.
  9. Yilmaz S, Uysal HB, Avcil M, Yilmaz M, Dağlı B, Bakış M, et al. Comparison of different methods for measurement of electrolytes in patients admitted to the intensive care unit. Saudi Med J 2016;37(3):262–267. DOI: 10.15537/smj.2016.3.13539.
  10. Gupta S, Gupta AK, Singh K, Verma M. Are sodium and potassium results on arterial blood gas analyzer equivalent to those on electrolyte analyzer? Indian J Crit Care Med 2016;20(4):233–237. DOI: 10.4103/0972-5229.180044.
  11. Taro Yamane. Statistics: An introductory analysis, 2nd edition. New York: Harper & Row; 1973. pp. 579–583.
  12. Priest G, Smith B, Heitz B. 9180 Electrolyte Analyzer Operator's Manual, 2nd edition. AVL Scientific corporation 1996; Available from:
  13. Radiometer - Blood Gas Analyzer. Abl80 Flex operator manual. Available from:
  14. Budak YU, Huysal K, Polat M. Use of a blood gas analyzer and a laboratory autoanalyzer in routine practice to measure electrolytes in intensive care unit patients. BMC Anesthesiol 2012;12:17. DOI: 10.1186/1471-2253-12-17.
  15. Nanda SK, Ray L, Dinakaran A. Agreement of arterial sodium and arterial potassium levels with venous sodium and venous potassium in patients admitted to intensive care unit. J Clin Diagn Res 2015;9(2):BC28–30. DOI: 10.7860/JCDR/2015/12418.5602.
  16. Doddamani P, Kasapura Shivashankar K, Chikkavaddaragudi Ramachandra S, Aman I, Maduvanahalli Nataraj S. Agreement of measurement between arterial and venous electrolyte levels in neonates in a Tertiary Care Hospital. J Lab Physicians 2020;12(1):20–26. DOI: 10.1055/s-0040-1713061.
  17. Trivedi M, Mohammad J, Mohd S. A comparative study on ABG analyzer versus laboratory analyzer for estimation of Electrolytes. Int J Health & Clin Res 2021;4(21):46–49. Available from:
  18. Prakash S, Bihari S, Lim ZY, Verghese S, Kulkarni H, Bersten AD. Concordance between point-of-care blood gas analysis and laboratory autoanalyzer in measurement of hemoglobin and electrolytes in critically ill patients. J Clin Lab Anal 2018;32(6):e22425. DOI: 10.1002/jcla.22425.
  19. Dipti Basavaraj Sanakal, Sagar Chandrakant Mhetre, Patil RS, Abdul Kayyum Shaikh. Reliability of blood gas analyzer for the measurement of electrolytes – A comparative study. Int J Clin Biochem Res 2016;3(4):376–379. DOI: 10.18231/2394-6377.2016.0007.
  20. Chacko B, Peter JV, Patole S, Fleming JJ, Selvakumar R. Electrolytes assessed by point-of-care testing - Are the values comparable with results obtained from the central laboratory? Indian J Crit Care Med 2011;15(1):24–29. DOI: 10.4103/0972-5229.78219.
  21. Burritt MF. Current analytical approaches to measuring blood analytes. Clin Chem 1990;36(8 Pt 2):1562–1566. PMID: 2387068.
  22. Lima-Oliveira G, Lippi G, Salvagno GL, Montagnana M, Picheth G, Guidi GC. Different manufacturers of syringes: A new source of variability in blood gas, acid-base balance and related laboratory test? Clin Biochem 2012;45(9):683–687. DOI: 10.1016/j.clinbiochem. 2012.03.007.
  23. van Berkel M, Scharnhorst V. Electrolyte-balanced heparin in blood gas syringes can introduce a significant bias in the measurement of positively charged electrolytes. Clin Chem Lab Med 2011;49(2): 249–252. DOI: 10.1515/CCLM.2011.047.
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.