Potassium Lab Test
Potassium Lab Test can be requested without a referral, and this overview covers what to expect. A potassium lab test measures the amount of potassium in your blood. Potassium is an electrolyte that helps nerves and muscles work properly, including the heart. This test is often ordered as part of a routine checkup or to check for conditions that affect potassium levels.
- Sample type
- blood
- Category
- General Wellness
- Turnaround
- 1-3 business days
- Price
- $37
- Referral
- Not required
A potassium lab test measures the amount of potassium in your blood. Potassium is an electrolyte that helps nerves and muscles work properly, including the heart. This test is often ordered as part of a routine checkup or to check for conditions that affect potassium levels.
What it measures
- Potassium — The main mineral being measured; normal levels help your heart and muscles function.
- Sodium — Often checked with potassium to see how well your body balances fluids.
- Chloride — Another electrolyte that helps maintain proper fluid balance.
- Bicarbonate — Helps show your body's acid-base balance, which can affect potassium.
Who it is for
A healthcare provider may order this test during a routine physical, if you take medications that affect potassium, or if you have symptoms like muscle weakness or irregular heartbeat.
Preparation
No special preparation is usually needed. You can eat and drink normally unless your provider tells you otherwise.
Results and what they mean
Results are reported as a number in millimoles per liter (mmol/L) and compared to a reference range. Your clinician interprets the result based on your health history and other tests. This is general information, not medical advice; only a qualified professional can diagnose or treat a condition.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the potassium lab test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
What can cause high or low potassium?
High potassium can be caused by kidney problems, certain medications, or a diet very high in potassium. Low potassium can result from vomiting, diarrhea, or diuretics. Your clinician will evaluate the cause.
Do I need to fast for this test?
Usually no fasting is required, but follow any instructions your provider gives you.
How long does it take to get results?
Results are typically available within 1 to 3 business days.
Can I eat bananas before the test?
Yes, unless your provider tells you to avoid high-potassium foods. A single banana is unlikely to change your result significantly.