Medicare Coverage of Laboratory Tests

What It Is

Diagnostic laboratory tests

What's Covered

Medicare Part A covers diagnostic laboratory tests performed for a hospital or skilled-nursing-facility inpatient.

Medicare Part B covers diagnostic laboratory tests for outpatients if performed by a Medicare-certified laboratory.

A diagnostic laboratory test must be prescribed by a doctor in order to diagnose an illness or condition. It doesn't include routine screening laboratory tests, such as those performed as part of a general physical examination, except as part of a one-time, initial "Welcome to Medicare" physical examination within the first six months of enrollment in Medicare.

Some preventive screening laboratory tests are covered by Medicare Part B for certain high-risk patients.

If you have a Medicare Part C Medicare Advantage plan: Medicare Part C Medicare Advantage plans, also called Medicare Advantage plans, must cover everything that's included in original Medicare Part A and Part B coverage. But sometimes a Part C plan covers more, with extra services or an expanded amount of coverage. (Co-payments for Part C plans may also be different than those for Part A or Part B.) To find out whether your plan provides extra coverage or requires different co-payments for diagnostic laboratory tests, contact the plan directly.

What Medicare Pays

The cost of inpatient laboratory services covered by Medicare Part A are part of the overall hospital charges for which Medicare Part A pays all but the Part A deductible and the patient coinsurance.

Medicare Part B pays 100 percent of the cost of Medicare-covered laboratory services.

Important: Regardless of the rules regarding any particular type of care, in order for Medicare Part A, Medicare Part B, or a Medicare Part C plan to provide coverage, the care must meet two basic requirements:

  • The care must be "medically necessary." This means that it must be ordered or prescribed by a licensed physician or other authorized medical provider, and that Medicare (or a Medicare Part C plan) agrees that the care is necessary and proper. For help getting your care covered, see FAQ: How Can I Increase the Odds That Medicare Will Cover My Medical Service?

  • The care must be performed or delivered by a healthcare provider who participates in Medicare.

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8 Comments So Far. Add Your Wisdom.

6 months ago

I have a 20+ year history of high cholesterol, and have been taking simvistatins to manage it. Medicare denied the initial blood test as 'medically unnecessary'. I need routine blood tests to continue taking the simvistatins and worry that I'll be billed for that too. I cannot afford the cost of my insurance and the cost of the lab work, but do not qualify for 'assistance'. Thoughts on this???

over 1 year ago

looking into for a patient in a skilled facility who underwent treatment for cancer and her physician is requesting CA-124 every 6 Months. Medicare is refusing to pay for this lab to be done. If so why? and what other test could be done?

about 2 years ago

i've been reviewing the new diabetic blood continuous system to pair with an insulin pump for glucose regulation. I have only injectible insulins and manual glucose machines, although I have been Type 1 diabetic since age 19 yrs. Am I eligible to use these new and better mechanisms reimbursed by Medicare and my supplement?

almost 3 years ago

I got a big Lab bill, i am on Medicare A/B, how do i get my Dr to say these tests are medically necessary and not routine. He tested me for Cholesterol and Diabetes, which i have a problem with and take medication for,

about 3 years ago

My surgeon ordered preop tests at thehospital where I work (I am age 70) for my convenience. My surgery is to be done inSt Louis. My Illinois hospital said my insurance would not pay for the tests. This is terrible. I am working because I cannotlive on social security. But I cannot afford these tests either so I guess I do without the knee replacement and use a walker the rest of my life.

about 4 years ago

Hi physican staff, Thanks for your question, it's a good one. I encourage you to ask one of our experts in the ask and answer section, as they will likely have the answer you are looking for. You can ask a questions here: . Thanks again for your questions! -- Emily | Community Manager

about 4 years ago

did not give timeframe in between lab. Example, will only pay every 3 months or 6 months or whatever, I am checking for a patient that is being billed and she had cardiac labs in Sept 2010 & our cardiologist I work for told her to return in 4 months which would be Feb 2011 with the same labs repeated prior to her visit. Well, she took it upon herself to have it done again in Dec 2010 and now medicare is denying saying not medically necessary. So my question is how oftern with a medical diagnosis to support it can labs be done in a given year if not screening labs?

over 4 years ago

Not very specific....I was trying to find out if my tumor marker is going to be covered. I can't afford it if not.


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