Laboratory Medicine Program

Potassium

Clinical Decription:
Clinical Description: The measurement of potassium is used mainly to monitor electrolyte balance in the diagnosis and treatment of primary aldosteronism, metabolic alkalosis, diarrhea, severe vomiting, diuretic administration, diabetic ketoacidosis, and other diseases. Potassium is primarily found intracellularly. In red blood cells the concentration is approximately 105 mmol/L or 23 times the concentration in plasma. The Na/ K-ATPase pump that is located in the cellular membrane maintains high intracellular concentrations. It continuously transports potassium into the cell. Potassium is excreted by the kidneys at a rate proportional to dietary intake. The kidney's response is to conserve potassium in instances of low total body potassium. Disturbances of potassium homeostasis can have serious consequences. For example, decreased extracellular levels can cause muscle irritability, increased heart rate and possibly cardiac arrest. Increased levels can cause muscle weakness, slow heart rate and possible cardiac arrest. Examples of conditions leading to potassium disturbance: hypokalemia as a result of insulin therapy of diabetic hyperglycemia where cellular uptake of glucose stimulated by insulin is accompanied by the uptake of potassium and water, and hyperkalemia as a result of diabetic ketoacidosis where potassium moves from intracellular space into plasma, as hydrogen ions move into the cells.
<br/><em>Bayer Advia 1650 Potassium package insert Bayer Advia Manufacturer's Manual</em>

Method: Automated method; c8000

Component Tests Used: n/a

Reference Ranges Used:
3.2 - 5.0 mmol/LPotassium levels on serum are slightly lower

Specimen Type: green,lithium heparin.PST(plasma separator)
Collected In: Lithium heparin
Volume: 3 mL (minimum: 1 mL)

Shipping: room temperature or 4C

Special Instructions: n/a

Testing Schedule(s): on demand.

Turnaround Time: 1 day

For more information, call 416.340.5227 or 1.866.865.5227