POTASSIUM

Code
400.1500
Name
POTASSIUM
Category
None
Department
Chemistry
Start Date
Expiration Date
Synonyms
K
CPT Codes
84132
Site
Main Lab
Reference Test
ATLAS Test Code

Specimen Information

Type

Gold, SST

Volume

1.0 ml

Transport Info

Room Temperature
14 day stability

Refrigerated
14 day stability

Frozen (Freeze Only once)
stable

Fasting Required?
False
Patient Instructions

Reference Range

4.0-6.4 mmol/L

Methodology

Ion-selective Electrode (ISE)

Clinical Significance

Used to monitor electrolyte balance in the diagnosis and treatment of disease conditions characterized by low or high blood potassium levels.

Potassium (K+) is the major positive ion within cells and is particularly important for maintaining the electric charge on the cell membrane, which is necessary for neuromuscular communication and for transporting nutrients into cells and waste products out of the cell. The concentration of potassium inside cells is about 30 times that in the blood and other extracellular fluids.Potassium levels are mainly controlled by the steroid hormone aldosterone (for more information see the aldosterone test), which increases excretion of potassium. Aldosterone is secreted from the adrenal gland in the presence of increasing levels of potassium. Metabolic acidosis (for example, caused by uncontrolled diabetes) or alkalosis (for example, caused by excess vomiting) can affect blood potassium because this ion shifts into or out of cells in exchange for hydrogen ions. For example, in acidosis some of the excess hydrogen ions will shift into cells in exchange for potassium ions being released from the cells.Small changes in the potassium concentration outside cells can have substantial effects on the activity of nerves and muscles. This is particularly true of the heart muscle. Low levels of potassium cause increased activity (which can lead to an arrhythmia), whereas high levels cause decreased activity. Either situation can lead to cardiac arrest in some circumstances. In normal people, taking potassium supplements or potassium-containing drugs is of no consequences, because the kidneys efficiently dispose of excess potassium.
Increased K+ levels (hyperkalemia) may indicate: - Addison’s disease (rare) - Crush injury (tissue trauma) - Hemolysis (red blood cell destruction) - Hypoaldosteronism (very rare) - Metabolic or respiratory acidosis - Renal failure- Transfusion of hemolyzed blood - Hyperkalemic periodic paralysis (potassium is elevated during episodes of paralysis)• Decreased K+ levels (hypokalemia) may indicate: - Cushing’s syndrome (rare) - Deficient potassium intake in the diet - Diarrhea - Hyperaldosteronism (very rare) - Renal tubular acidosis (rare) - Vomiting - Excessive potassium loss because of a GI (gastrointestinal)disorder -- e.g., villous adenoma (tumor) - Hypokalemic periodic paralysis (low potassium during an episode of paralysis) - Diuretic use.

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