title: Haemolysis index--an estimate of preanalytical quality in primary health care.
abstract: BACKGROUND
  Haemolysis is usually caused by inadequate specimen collection or preanalytical handling, and is suggested to be a suitable indicator of pre-analytical quality. We investigated the prevalence of detectable haemolysis in all routine venous blood samples to identify differences in preanalytical quality.
  
  
  METHODS
  Haemolysis index (HI) values were obtained from a Vitros 5,1 in the routine clinical chemistry laboratory for samples collected in primary health care centres (PHCs), nursing homes, and a hospital emergency department (ED). Haemolysis was defined as a HI > or =15 (detection limit).
  
  
  RESULTS
  Samples from the PHC with the highest prevalence of haemolysis were 6.1 times (95% confidence interval (CI) 4.0-9.2) more often haemolysed compared to the centre with the lowest prevalence. Of the samples collected in primary health care, 10.4% were haemolysed compared to 31.1% in the ED (p<0.001). A notable difference in haemolysed samples was found between the ED section staffed by emergency medicine physicians and the section staffed by primary health care physicians (34.8% vs. 11.3%, p<0.001).
  
  
  CONCLUSIONS
  The significant variation in haemolysis indices among the investigated units is likely to reflect varying preanalytical conditions. The HI is a valuable tool for estimation and follow-up of preanalytical quality in primary health care.
authors: Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden. johan.soderberg@medbio.umu.se
authors: Johan
authors: J
authors: Söderberg
authors: P Andreas
authors: PA
authors: Jonsson
authors: Olof
authors: O
authors: Wallin
authors: Kjell
authors: K
authors: Grankvist
authors: Johan
authors: J
authors: Hultdin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001800:Blood Specimen Collection / Q000592:standards*; D005260:Female; D006461:Hemolysis / Q000502:physiology*; D006801:Humans; D007755:Laboratories, Hospital / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009996:Osmotic Fragility; D011320:Primary Health Care / Q000592:standards*; D011785:Quality Assurance, Health Care / Q000592:standards