Potassium is the
primary intracellular cation. It is also an integral part of the transmission of
nerve impulses. It participates in the
sodium-potassium pump in the body.
Unhemolyzed serum
should be used because hemolysis will markedly increase the potassium values
because potassium is present in large amounts inside the cell.
Clinical Significance
1. Hyperkalemia
– increased concentration of potassium in the bloodstream. It’s found in the
following conditions:
•
Decreased renal excretion
•
Acute or chronic renal
failure
•
Hypoaldosteronism
•
Addison’s disease
•
Diuretic
·
Cellular shift
•
Acidosis
•
Muscle/cellular injury
•
Chemotherapy
•
Leukemia
•
Hemolysis
Increased intake
Oral or IV potassium replacement therapy
-
Artifactual
Sample
hemolysis
Thrombocytosis
Prolonged
tourniquet use of excessive fist clenching
2. Hypokalemia – decreased concentration of potassium in
the blood stream, seen in the following conditions:
GI loss
- Vomiting
- Diarrhea
- Gastric suction
- Intestinal tumor
- Malabsorption
- Cancer therapy
-
Large doses of laxatives
Normal values:
K = 3.5-5.3
•
Plasma
and serum: 3.4 – 5.0 mmol/L
•
Urine:
25 -125 mmol/L
