- Rise in the level of serum potassium that occurs due to excessive leakage of potassium from cells.
- This potassium leakage may occur during or after blood sampling.
- It is thus a laboratory artifact rather than a true biological abnormality.
Pseudohyperkalaemia Typical Causes:
- Haemolysis during venipuncture.
- Excessive tourniquet time
- Excessive fist clenching during phlebotomy (considered to cause efflux of potassium from the muscle cells into the venous system);
- Delay in the processing of the blood specimen.
- People with 'leakier' cell membranes.
Pseudohyperkalaemia Associations:
- Myeloproliferative disorders
- Platelet - platelet activation, thrombocytosis
- Red cell - polycythaemia
- White cell - leukaemia, leukocytosis,
Pseudohyperkalaemia Other Important Points:
- First reported by Hartmann and Mellinkoff in 1955.
- The presence of pseudohyperkalaemia may be masked when it occurs in the presence of real hypokalaemia as potassium can move back into the intracellular space in vitro.
- "... pseudohyperkalemia in serum seems to be the result of two independent and sequential mechanisms: (1) degranulation of platelets, which offers a potassium load to the surrounding serum at the time of clot formation in vitro, and (2) transfer of a part of this potassium load back into blood cells in order to maintain electrolyte and osmotic homeostasis." (1)
Reference:
1) - Nikolaos Sevastos, George Theodossiades, & Athanasios J. Archimandritis. Pseudohyperkalemia in Serum: A New Insight into an Old Phenomenon. Clin Med Res. 2008 May; 6(1): 30–32.
Tags: Haemolysis - Hyperkalaemia - Hypokalaemia - Leukocytosis - Platelet Degranulation - Polycythaemia - Potassium - Pseudohyperkalaemia - Thrombocytosis - VenipunctureTags: Medicine In The News
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Posted by Medicalchemy
Medicalchemy Group: Clinical Trials - History of Medicine - Images - Mnemonics - Syndromes - Tests -
Acute Medicine - Anaesthesiology - Anatomy - Anthropology - Biochemistry - Cardiology - Dentistry - Dermatology - Drug ADR - Drugs - Duplication Sites - Embryology - Emergency Medicine - Endocrinology - Epidemiology - Family Medicine - Forensic Medicine - Gastroenterology - Genes - Genetics - Geriatrics - Gynecology - Haematology - Health Informatics - Hepatology - Immunology - Infection - Intensive Care - Medical Dictionary - Medical Education - Medical Geography - Medical Statistics - Metabolic Medicine - Microbiology - Nephrology - Neuroanatomy - Neuroscience - Nuclear Medicine - Nutrition - Obstetrics - Occupational Health - Oncology - Ophthalmology - Orthopaedics - Otolaryngology - Paediatrics - Palliative Care - Parasitology - Pathology - Pharmacology - Physiology - Proteomics - Psychiatry - Public Health - Radiology - Respiratory - Rehabilitation - Rheumatology - Sports Medicine - Surgery - Toxicology - Tropical Medicine - Urology - Vascular - Virology
