In patients with moderate to severe hyperkalemia, potassium measurements obtained via blood gas analyzer differ significantly from those of biochemistry analyzers, a new Turkish study finds.
“Although much faster than central laboratory biochemistry analyzer results, serum potassium values attained by blood gas analyzers may mislead physicians to the belief that the patient does not have a life-threatening hyperkalemia,” Seyyid Bilal Acikgoz, MD, and colleagues of Sakarya Training and Research Hospital in Turkey wrote in the American Journal of Emergency Medicine.
The investigators reviewed the medical records of 118 patients who presented to the emergency department of their hospital with serum potassium levels of 6 mmol/L and above. No exclusions were made due to underlying cause of disease or co-existing conditions.
Results showed that average serum potassium level by biochemistry analyzer was 6.78 mmol/L, but 6.16 mmol/L by blood gas analyzer – a difference of 0.62 mmol/L.
Previous studies have yielded mixed results. A recent study of 11,000 patients published by Mirzazadeh et al in the Emergency Medicine Journal (2015; published online ahead of print) found sufficient agreement in potassium measurements for clinical care. Patients had milder forms of hyperkalemia, however, which could be relevant, according to the researchers. A discrepancy of up to 1 mmol/L would indicate different management strategies in patients with severe hyperkalemia.
Many clinicians base their treatment decisions on blood gas analyzer results obtained at the point-of-care, Dr. Acikgoz and colleagues noted. A study by Jose et al, also published in the Emergency Medicine Journal (2008;25:510-513), found that roughly half of clinicians working in intensive care rely on this test.
Since the current study involved a small number of patients, future studies with larger sample populations are warranted.