The preventative frequency is once every 5 years. However, the statement "my current medical problem list" sounds like you are "at risk" which would fall under the diagnostic lab test benefit. Diagnostic tests can be performed more frequently but are not "free" (included in the premium). It would be subject to the Part B 20% coinsurance unless you have a Medicare Supplement (Medigap) that covers the coinsurance. Ask your provider if the test would be coded as diagnostic instead of preventative.
"Benefit Category
Diagnostic Laboratory Tests
When monitoring long term anti-lipid dietary or pharmacologic therapy and when following patients with borderline high total or LDL cholesterol levels, it is reasonable to perform the lipid panel annually. A lipid panel at a yearly interval will usually be adequate while measurement of the serum total cholesterol or a measured LDL should suffice for interim visits if the patient does not have hypertriglyceridemia.
Any one component of the panel or a measured LDL may be medically necessary up to six times the first year for monitoring dietary or pharmacologic therapy. More frequent total cholesterol HDL cholesterol, LDL cholesterol and triglyceride testing may be indicated for marked elevations or for changes to anti-lipid therapy due to inadequate initial patient response to dietary or pharmacologic therapy. The LDL cholesterol or total cholesterol may be measured three times yearly after treatment goals have been achieved.
If no dietary or pharmacological therapy is advised, monitoring is not necessary.
When evaluating non-specific chronic abnormalities of the liver (for example, elevations of transaminase, alkaline phosphatase, abnormal imaging studies, etc.), a lipid panel would generally not be indicated more than twice per year."
Reference:
https://www.cms.gov/medicare-covera...iod=0&NCDId=102&ncdver=2&bc=AAQAAAAAQEAAAA==&