title: Pseudohyperkalaemia in leukaemic patients: the effect of test tube type and form of transport to the laboratory.
abstract: BACKGROUND
  The present study was aimed at determining the effect of the tube type used for primary sample collection and the manner of transport prior to assessment (either manual or by pneumatic tube) on the degree of pseudohyperkalaemia in leukaemic patients.
  
  
  METHODS
  Blood from six leukaemic patients was collected into seven primary sample tubes (Monovette®, Sarstedt): sample A, heparinized blood gas syringe (potassium reference value); sample B, plasma Li-heparin without separator gel; sample C, plasma Li-heparin with separator gel; and sample D, serum with separator gel. The primary sample tubes designated B, C and D were transported to the laboratory manually. Duplicates of the same sample tubes, B(PT), C(PT) and D(PT), were sent to the laboratory by pneumatic tube.
  
  
  RESULTS
  In patients with chronic lymphocytic leukaemia (CLL), there was no increase in the concentration of potassium in samples B, C and D when compared to the reference value. Transport of the samples by pneumatic tube led to a pronounced increase in potassium concentration in samples B(PT) and C(PT), whereas there was no increase in sample D(PT) when compared to the reference value. In the patient with chronic myeloid leukaemia (CML), an increase in potassium concentration occurred in sample D and in samples B(PT), C(PT) and D(PT). A similar finding was observed in the patient with acute lymphocytic leukaemia (ALL), furthermore with an extremely high concentration of potassium in samples C and C(PT).
  
  
  CONCLUSIONS
  Manual transport of non-coagulable blood (plasma Li-heparin without separator gel) to the laboratory results in the least possible artificial increase in potassium concentration in the sample.
authors.affiliation: Department of Clinical Biochemistry, University Hospital Brno, Czech Republic.
authors.forename: Milan
authors.initials: M
authors.lastname: Dastych
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Cermáková
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006947:Hyperkalemia / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D012016:Reference Values; D013048:Specimen Handling
chemical_list: D011188:Potassium
keywords: Leukaemia; analytes; clinical studies; electrolytes