GPR: 2021 - Week 35

From MGH Learn Pathology

Clinical history

25F presents as a transfer for infective mitral valve endocarditis. Peripheral blood was drawn for admission labs.


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All of the above
  • Lipemia is the 2nd most frequent endogenous interferent
  • Significant analytical errors for many testing modalities
  • Occurs when serum triglyceride levels exceed 400 mg/dL
  • Detection: Visual inspection vs spectrophotometric analysis (L-index; automated)
  • Ultracentrifugation the preferred method to eliminate this effect
 

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Na & Cl

  • Volume displacement: Electrolytes
  • Plasma consists of ~92% of water and 8% of lipids
  • Methods measuring electrolytes that use total plasma volume (flame photometry or indirect potentiometry) leads to underestimation (pseudohyponatremia)
  • Methods that measure concentration of electrolytes only in the water phase without dilution (direct potentiometry) are unaffected
 

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ALT

  • Spectrophotometric methods: Lipoprotein particles in the sample can absorb light (Including ALT)
  • Immunoassays: Lipoproteins can interfere with antigen-antibody interactions
 


Dr. Grace Mahowald
  • Soleimani N, Mohammadzehed S, Asadian. 2020. Lipemia Interferences in Biochemical Tests, Investigating the Efficacy of Different Removal Methods in comparison with Ultracentrifugation as the Gold Standard. Journal of Analytical Methods in Chemistry.
  • Krasowski D. 2019. Educational Case: Hemolysis and Lipemia Interference with Laboratory Testing. Academic Pathology.
  • Nikolac N. 2014. Lipemia: Causes, interference mechanisms, detection and management. Biochemica Medica.
  • Dimeski G et al. 2006. Effects of Hyperlipidemia on Plasma Sodium, Potassium, and Chloride Measurements by an Indirect Ion-Selective Electrode Measuring System. Clinical Chemistry.
  • Pseudohyponatremia image from: https://nephsim.com/case-29-diagnosis-conclusions/
  • Cuvette image from: www.alibaba.com

This week's Gross Pathology Roundup was presented by Daniel Pearson MD, PhD on 2021-08-30.