Diagnostic Use
Refer to Sodium and Potassium
Limitations / Interference
Avoid hemolyzed samples for potassium. Hemolyzed samples may give incorrect elevated potassium. Intracellular potassium concentration is 30–50 times greater than that of
extracellular serum or plasma.
Samples exposed to benzalkonium salts present in certain blood catheter devices will cause
falsely elevated sodium and potassium measurements.8
Iron at 1 g/dL increases the potassium result in serum/plasma at 2.69 mmol/L (2.69 mEq/L) by
17% and 4.54 mmol/L (4.54 mEq/L) by 11%.
Citrate at 1 g/dL decreases the chloride result in serum/plasma at 82.4 mmol/L (82.4 mEq/L) by
-12%.
Fluoride at 1 g/dL increases the chloride result in serum/plasma at 81.7 mmol/L (81.7 mEq/L)
by 40% and 101 mmol/L (101 mEq/L) by 55%.
Iodine at 50 mg/dL increases the chloride result in serum/plasma at 82.2 mmol/L (82.2 mEq/L)
by 16%.
Bromide at 200 mg/dL increases the chloride result in serum/plasma at 82.1 mmol/L
(82.1 mEq/L) by 55% and 101 mmol/L (101 mEq/L) by 36%.
Salicylate at 50 mg/dL increases the chloride result in serum/plasma at 98.5 mmol/L
(98.5 mEq/L) by 11% and 101 mmol/L (101 mEq/L) by 12%.
Ibuprofen at 500 mg/dL increases chloride results in urine at 47.2 mmol/L (47.2 mEq/L) by
18%.
Ofloxacin at 90 mg/dL decreases chloride results in urine at 55.8 mmol/L (55.8 mEq/L) by
-11%.
Assay results obtained at individual laboratories may vary from the data presented.
As with any chemical reaction, you must be alert to the possible effect of unknown
interferences from medications or endogenous substances. The laboratory and physician must
evaluate all patient results in light of the total clinical status of the patient.
Samples exposed to benzalkonium salts present in certain blood catheter devices will cause falsely elevated sodium and potassium measurements.