Potassium (K+) (Serum)

Clinical definition of the Potassium test
Potassium is an electrolyte that works with other electrolytes, such as sodium, chloride, and bicarbonate (total CO2) to help maintain and regulate the amount of fluid (water and electrolyte) balance in the body, stimulate muscle contraction, and maintain a stable acid-base balance in blood and tissue cells. Potassium also assists in muscle building, transmitting electrical signals between cells and nerves. It is very important and essential in regulating the normal rhythm of heart beats. Potassium deficiency may be caused by excessive diarrhea and vomiting.

Why is the Potassium test done?
This test measures the amount of potassium in the blood. It is done to determine whether potassium concentration is within normal limits. A potassium test may also be done in the following cases:-

  • As a routine medical exam as part of an electrolyte or metabolic panel
  • To help evaluate an electrolyte imbalance
  • To monitor chronic or acute hyperkalemia or hypokalemia
  • At regular intervals to check for the effect of a medication, for too low or too high potassium levels
  • To diagnose or monitor kidney disease
  • To check for signs of high blood pressure or heart problems
  • For a suspected case of metabolic acidosis (caused by uncontrolled diabetes) or alkalosis (caused by excess vomiting)
  • Occasionally, the potassium test may be done in persons who are having an attack of paralysis

What are the common signs/symptoms when the Potassium test is done?
Symptoms are fairly nonspecific and generally include:-

  • Dry skin
  • Weakness
  • Fatigue
  • Malaise
  • Slow reflexes
  • Palpitations 
  • Muscle weakness
  • Myalgia
  • Muscle cramps
  • Constipation

Further complications may show more complex symptoms such as:-

  • Elevation of blood pressure
  • Cardiac arrhythmia
  • Mild hyperventilation
  • Metabolic acidosis
  • Electrolyte imbalance

Who should do the Potassium test (Target population)?
Persons showing the above signs & symptoms or who may be suffering from excessive diarrhea and vomitting.

What should I do before the Potassium test?

Specimen type

Specimen collection procedure

Preparatory instructions before the test *


(Blood Sample)


(Collection of blood from a vein, usually from the arm)

No Fasting Required.

No other special preparations required.

*Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my Potassium test results?

Reference Range*

Normal range


3.5 to 5.1 mmol/L


3.5 to 5.1 mmol/L

0 - 1 week

3.2 - 5.7 mmol/l

1 wk - 1 month

3.4 - 6.2 mmol/l

1 - 6 months

3.5 - 5.8 mmol/l

6 months - 1 year

3.5 - 6.3 mmol/l

> 1 year

3.3 - 4.7 mmol/l

24 hrs Urine

40-80 meq/day

‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’

Diseases/conditions related to the Potassium test

  • Kidney failure
  • Red blood cell destruction
  • Metabolic or respiratory acidosis
  • Addison's disease 
  • Hypoaldosteronism
  • Chronic Diarrhea
  • Hyperaldosteronism
  • Hypokalemic periodic paralysis 
  • Cushing's syndrome 
  • Renal tubular acidosis 
  • Acute adrenal crisis
  • Acute bilateral obstructive uropathy
  • Acute nephritic syndrome
  • Bulimia
  • Chronic kidney failure
  • Cushing's disease
  • Diabetic ketoacidosis
  • Primary thrombocythemia
  • Renal tubular acidosis - distal
  • Rhabdomyolysis
  • Thyrotoxic periodic paralysis

Other tests related to the Potassium test

  • Chloride
  • Sodium
  • Bicarbonate (or Total CO2)
  • Electrolyte panel
  • Aldosterone
  • Renin
  • Comprehensive Metabolic Panel (CMP)
  • Basic Metabolic Panel (BMP)

Synonyms : Hypokalemia test
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Potassium (Serum)