Reducing the incidence of pseudohyperkalemia by avoiding making a fist during phlebotomy: A quality improvement report

Masanori Seimiya, Toshihiko Yoshida, Yuji Sawabe, Kazuyuki Sogawa, Hiroshi Umemura, Kazuyuki Matsushita, Fumio Nomura

Research output: Contribution to journalArticle

16 Citations (Scopus)


Background: Pseudohyperkalemia is uncommon, but important. Local release of potassium caused by contraction of the forearm muscles from a tightly clenched fist or repeated fist clenching during phlebotomy is a recognized cause of pseudohyperkalemia. We investigated the use of a standard protocol to avoid fist clenching during phlebotomy. Study Design Quality improvement report. Setting & Participants In 7 healthy volunteers, 10 blood samples were collected over 10-second intervals after 20 repeated fist clenching and unclenching movements. In 86 healthy volunteers, 3 blood samples were collected with and without prior fist clenching. Between September 1, 2006, and June 30, 2007, peripheral venous blood samples were collected from 73,846 outpatients at Chiba University Hospital without a protocol to avoid fist clenching. Between July 1, 2007, and March 31, 2009, blood samples were collected from 171,053 outpatients using the protocol. Quality Improvement Plan After July 1, 2007, blood samples were collected from the basilic or cephalic vein without making a fist or by making a fist using minimal gripping strength. Also, when multiple specimens were obtained from 1 patient, the specimen for measuring serum electrolytes was obtained after the other specimens. Outcomes & Measurements Pseudohyperkalemia, defined as unexplained serum potassium level

Original languageEnglish
Pages (from-to)686-692
Number of pages7
JournalAmerican Journal of Kidney Diseases
Issue number4
Publication statusPublished - Oct 2010
Externally publishedYes



  • clenching
  • Index Words
  • make a fist
  • order of draw
  • phlebotomy
  • Pseudohyperkalemia

ASJC Scopus subject areas

  • Nephrology
  • Medicine(all)

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