The date of service on a laboratory claim looks like an administrative field. It is not — it determines whether the test is bundled into a hospital claim or billed to Medicare directly by the laboratory. Getting it wrong produces either a denial or a claim that should never have been submitted.
The date of service for a clinical laboratory test is normally the date the specimen was collected. Under the 14-day rule, it moves to the date the test was performed when specific conditions are met, which changes who bills Medicare: the hospital, or the laboratory directly.
The default is simple: the date of service is the date the specimen was collected.
That default has a consequence that is not obvious. If the specimen was collected during a hospital outpatient encounter, a date of service falling inside that encounter means the test belongs to the hospital's claim — bundled, billed by the hospital, with the laboratory paid by the hospital rather than by Medicare.
The 14-day rule is the exception that moves the date of service to the date the test was performed. When it applies, the test is no longer part of the hospital encounter, and the laboratory bills Medicare directly.
So the question is never really "what date goes in the box". It is "who is entitled to bill for this test", and the date is how the answer is expressed.
For a test on a stored specimen from a hospital outpatient, the date of service becomes the performance date when all of the following hold:
All of them, not a majority. A test ordered on day twelve does not qualify, however clearly the remaining conditions are met.
Since 1 January 2018, advanced diagnostic laboratory tests and molecular pathology tests have been treated differently. Where such a test is performed on a specimen collected during a hospital outpatient encounter and performed after the patient is discharged, the laboratory bills Medicare directly — regardless of when the test was ordered.
The 14-day wait does not apply to these. This is the part most often applied incorrectly, in both directions: laboratories that keep waiting fourteen days for tests that no longer require it, and laboratories that extend the exception to tests which do not qualify for it.
Note the scope carefully. The exception is written around outpatient specimens. It does not convert every post-discharge molecular test into a direct-bill situation.
Date of service is the structural issue. The volume issue is medical necessity.
Coverage determinations. Laboratory tests are among the most heavily governed by National and Local Coverage Determinations, which specify the diagnoses that support each test. A test ordered for a condition outside that list is not payable, however clinically reasonable the order was. Because these are set locally, the same test and diagnosis can be covered in one jurisdiction and not another.
Panel unbundling. Where a panel exists, billing its components individually generally pays less, not more, and edits are designed to catch it. Panels are also defined precisely — a panel billed when only some of its components were performed is a different problem, and a more serious one.
Advance Beneficiary Notices. Where a test is likely to be denied as not reasonable and necessary, an ABN obtained before the service is what allows the patient to be billed. Obtained afterwards, or not at all, the write-off is yours. In a high-volume laboratory the ABN workflow is the difference between a non-covered test being a collectable charge and a write-off.
Laboratories run on claim volume rather than claim value, which changes what matters. A small percentage failure rate that a surgical practice would absorb is, at laboratory volumes, a number worth a dedicated process.
Send a sample of claims for hospital-collected specimens and we will tell you which were billed by the right party. No charge, no obligation.
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