title: Delay in specimen processing-major source of preanalytical variation in serum electrolytes.
abstract: OBJECTIVE
  To evaluate the stability of electrolytes in serum samples due to delay in analysis in a tertiary care government hospital in India, and the maximum time delay acceptable between sample centrifugation and analysis.
  
  
  METHODS
  We estimated serum electrolytes of 400 samples with different time intervals between centrifugation and sample analysis on automated analyser.
  
  
  RESULTS
  Values were compared using repeated measure ANNOVA and acceptable limit change using in house QC values of 6 months. During the time interval between centrifugation and sample analysis, the samples were kept uncovered in sample cups in the laboratory. Potassium values show significant changes within 1 h (T1, p<0.01) but sodium (T2, p <0.01) and chloride (T2, p <0.001) values are acceptable up to a time delay of 3 h between sample centrifugation and analysis.
  
  
  CONCLUSIONS
  Samples for electrolytes should be analysed within 1-2 h of centrifugation and if there is any delay in analysis, the samples should be stored under proper conditions.
authors: Senior Resident, Department of Biochemistry, Pgimer and Dr RML Hospital , New Delhi, India .
authors: Ankur
authors: A
authors: Baruah
authors: Assistant Professor, Department of Biochemistry, Pgimer and Dr RML Hospital , New Delhi, India .
authors: Parul
authors: P
authors: Goyal
authors: Senior Resident, Department of Biochemistry, Pgimer and Dr RML Hospital , New Delhi, India .
authors: Saket
authors: S
authors: Sinha
authors: Head of Department, Department of Biochemistry, Pgimer and Dr RML Hospital , New Delhi, India .
authors: K L
authors: KL
authors: Ramesh
authors: Senior Resident, Department of Biochemistry, Lady Hardinge Medical College , New Delhi, India .
authors: Rashmirasi
authors: R
authors: Datta
keywords: Acceptable limit change; Sample stability; Serum electrolyte
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