What It Is
Diagnostic laboratory tests
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.