Startseite Medizin The different serum albumin assays influence calcium status in haemodialysis patients: a comparative study against free calcium as a reference method
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The different serum albumin assays influence calcium status in haemodialysis patients: a comparative study against free calcium as a reference method

  • Osama Eisa EMAIL logo , Mohammed Dafaalla , Mark Wright , Muhammad Faisal , Kevin Stuart und Nuthar Jassam ORCID logo
Veröffentlicht/Copyright: 13. Dezember 2024
Clinical Chemistry and Laboratory Medicine (CCLM)
Aus der Zeitschrift Clinical Chemistry and Laboratory Medicine (CCLM) Band 63 Heft 5

Abstract

Objectives

Accurate assessment of calcium levels is crucial for optimal management of regular Haemodialysis (HD) patients. Different calcium adjustment equations and albumin methods; including bromocresol purple (BCP) and bromocresol green (BCG) assays are employed by laboratories, which cause considerable discrepancies between reported results. The aim of this study is to assess the influence of albumin assays on calcium status in stable haemodialysis patients against free calcium (fCa) as a gold standard test.

Methods

A total of 103 paired serum and fCa samples were collected from a cohort of stable HD patients. Albumin levels were measured by either the BCP or BCG method, and samples were also analysed for the total calcium (T.Ca), phosphate, bicarbonate, and pH levels. The performance of BCG-based and BCP-based adjusted calcium equations was compared using Z-scores scatter plots, intraclass correlation coefficient and Cohen Kappa statistic, with fCa being the reference standard.

Results

Unadjusted T.Ca achieved a 70 % overall classification agreement with fCa and identified 61 % of the “true” hypocalcaemic samples. Adjusted calcium concentrations, calculated by either BCP- or BCG-based equation, were poor predictors of fCa; with more than 50 % of the hypocalcaemic samples being misclassified as normocalcaemic. Notably, both equations misclassified the calcium status in 5 (4.9 %) patients with severe hypocalcaemia (i.e., potentially requiring calcium infusion) as mild hypocalcaemia.

Conclusions

Our study showed evidence of hidden hypocalcaemia being missed by the current practice of using adjusted calcium in HD patients. Therefore, we recommend abandoning the adjustment procedure in samples from stable HD patients in favour of fCa measurement.

Keywords: calcium status; renal dialysis; albumin assays
Corresponding author: Dr. Osama Eisa, Department of Clinical Biochemistry, Leeds University Teaching Hospitals NHS Trust, Leeds, UK, E-mail:

  1. Research ethics: The study protocol was approved by the West Midlands – Solihull Research Ethics Committee (REC Ref. 22/WM/0130) and the Health and Care Research Wales (HCRW).

  2. Informed consent: Not applicable.

  3. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission. NJ conceived the study and developed the methodology, OE and MD conducted the study. KS and MW supported the study development. NJ and OE wrote the first draft. MF was involved in the statistical analysis. All authors reviewed and approved the final version of the manuscript.

  4. Use of Large Language Models, AI and Machine Learning Tools: None declared.

  5. Conflict of interest: The authors state no conflict of interest.

  6. Research funding: None declared.

  7. Data availability: Not applicable.

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Supplementary Material

This article contains supplementary material (https://doi.org/10.1515/cclm-2024-1030).

Received: 2024-09-03
Accepted: 2024-11-28
Published Online: 2024-12-13
Published in Print: 2025-04-28

© 2024 Walter de Gruyter GmbH, Berlin/Boston

Artikel in diesem Heft

  1. Frontmatter
  2. Editorial
  3. Are the benefits of External Quality Assessment (EQA) recognized beyond the echo chamber?
  4. Reviews
  5. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part I – EQA in general and EQA programs in particular
  6. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part II – EQA cycles
  7. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part III – EQA samples
  8. Behind the scenes of EQA–characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part IV – Benefits for participant laboratories
  9. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part V – Benefits for stakeholders other than participants
  10. Opinion Papers
  11. Not all biases are created equal: how to deal with bias on laboratory measurements
  12. Krebs von den Lungen-6 (KL-6) as a diagnostic and prognostic biomarker for non-neoplastic lung diseases
  13. General Clinical Chemistry and Laboratory Medicine
  14. Evaluation of performance in preanalytical phase EQA: can laboratories mitigate common pitfalls?
  15. Point-of-care testing improves care timeliness in the emergency department. A multicenter randomized clinical trial (study POCTUR)
  16. The different serum albumin assays influence calcium status in haemodialysis patients: a comparative study against free calcium as a reference method
  17. Measurement of 1,25-dihydroxyvitamin D in serum by LC-MS/MS compared to immunoassay reveals inconsistent agreement in paediatric samples
  18. Knowledge among clinical personnel on the impact of hemolysis using blood gas analyzers
  19. Quality indicators for urine sample contamination: can squamous epithelial cells and bacteria count be used to identify properly collected samples?
  20. Reference Values and Biological Variations
  21. Biological variation of cardiac biomarkers in athletes during an entire sport season
  22. Increased specificity of the “GFAP/UCH-L1” mTBI rule-out test by age dependent cut-offs
  23. Cancer Diagnostics
  24. An untargeted metabolomics approach to evaluate enzymatically deconjugated steroids and intact steroid conjugates in urine as diagnostic biomarkers for adrenal tumors
  25. Cardiovascular Diseases
  26. Comparative evaluation of peptide vs. protein-based calibration for quantification of cardiac troponin I using ID-LC-MS/MS
  27. Infectious Diseases
  28. The potential role of leukocytes cell population data (CPD) for diagnosing sepsis in adult patients admitted to the intensive care unit
  29. Letters to the Editor
  30. Concentrations and agreement over 10 years with different assay versions and analyzers for troponin T and N-terminal pro-B-type natriuretic peptide
  31. Does blood tube filling influence the Athlete Biological Passport variables?
  32. Influence of data visualisations on laboratorians’ acceptance of method comparison studies
  33. An appeal for biological variation estimates in deep immunophenotyping
  34. Serum free light chains reference intervals for the Lebanese population
  35. Applying the likelihood ratio concept in external quality assessment for ANCA
  36. A promising new direct immunoassay for urinary free cortisol determination
https://doi.org/10.1515/cclm-2024-1030
Schlagwörter für diesen Artikel
calcium status; renal dialysis; albumin assays

Artikel in diesem Heft

  1. Frontmatter
  2. Editorial
  3. Are the benefits of External Quality Assessment (EQA) recognized beyond the echo chamber?
  4. Reviews
  5. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part I – EQA in general and EQA programs in particular
  6. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part II – EQA cycles
  7. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part III – EQA samples
  8. Behind the scenes of EQA–characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part IV – Benefits for participant laboratories
  9. Behind the scenes of EQA – characteristics, capabilities, benefits and assets of external quality assessment (EQA): Part V – Benefits for stakeholders other than participants
  10. Opinion Papers
  11. Not all biases are created equal: how to deal with bias on laboratory measurements
  12. Krebs von den Lungen-6 (KL-6) as a diagnostic and prognostic biomarker for non-neoplastic lung diseases
  13. General Clinical Chemistry and Laboratory Medicine
  14. Evaluation of performance in preanalytical phase EQA: can laboratories mitigate common pitfalls?
  15. Point-of-care testing improves care timeliness in the emergency department. A multicenter randomized clinical trial (study POCTUR)
  16. The different serum albumin assays influence calcium status in haemodialysis patients: a comparative study against free calcium as a reference method
  17. Measurement of 1,25-dihydroxyvitamin D in serum by LC-MS/MS compared to immunoassay reveals inconsistent agreement in paediatric samples
  18. Knowledge among clinical personnel on the impact of hemolysis using blood gas analyzers
  19. Quality indicators for urine sample contamination: can squamous epithelial cells and bacteria count be used to identify properly collected samples?
  20. Reference Values and Biological Variations
  21. Biological variation of cardiac biomarkers in athletes during an entire sport season
  22. Increased specificity of the “GFAP/UCH-L1” mTBI rule-out test by age dependent cut-offs
  23. Cancer Diagnostics
  24. An untargeted metabolomics approach to evaluate enzymatically deconjugated steroids and intact steroid conjugates in urine as diagnostic biomarkers for adrenal tumors
  25. Cardiovascular Diseases
  26. Comparative evaluation of peptide vs. protein-based calibration for quantification of cardiac troponin I using ID-LC-MS/MS
  27. Infectious Diseases
  28. The potential role of leukocytes cell population data (CPD) for diagnosing sepsis in adult patients admitted to the intensive care unit
  29. Letters to the Editor
  30. Concentrations and agreement over 10 years with different assay versions and analyzers for troponin T and N-terminal pro-B-type natriuretic peptide
  31. Does blood tube filling influence the Athlete Biological Passport variables?
  32. Influence of data visualisations on laboratorians’ acceptance of method comparison studies
  33. An appeal for biological variation estimates in deep immunophenotyping
  34. Serum free light chains reference intervals for the Lebanese population
  35. Applying the likelihood ratio concept in external quality assessment for ANCA
  36. A promising new direct immunoassay for urinary free cortisol determination
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