Laboratory Date of Service

Clinical laboratory and pathology specimens

The date of service (DOS) for clinical laboratory tests and the technical component of physician pathology services is governed by 42 CFR 414.510. The DOS is a required field on all Medicare claim types.

A laboratory service can span several dates: the specimen collection, the performance of the test, result generation and the report may fall on different days. When an exception places the DOS on the date the test was performed that is the date the laboratory performs the analysis, as reflected by results summarized in the laboratory or pathology report. 

Accurate determination of date of service depends on correct identification of whether the specimen was collected during a hospital encounter. Incomplete or inaccurate information at the time of ordering may affect billing and responsibility for services. This article explains which date to report as the DOS: the general rule, the two-calendar-day variation, the exceptions, and the documentation each requires.

Definitions

Specimen: A sample of body fluid or tissue collected for laboratory testing (CLIA, 42 CFR Part 493). 

Archived specimen: A specimen stored more than 30 calendar days before testing (42 CFR 414.510(b)(2)(ii)).  

Advanced diagnostic laboratory test (ADLT): A clinical diagnostic laboratory test covered under Medicare Part B that is offered and furnished only by a single laboratory and either analyzes multiple biomarkers with a unique algorithm to yield a single result, or is cleared or approved by the FDA (42 CFR 414.502).

MAAA: is a laboratory assay that integrates the measurement of multiple biomarkers (e.g., DNA, RNA, proteins, or other analytes) obtained from a single or multiple patient specimens and applies a validated computational algorithm to combine these data into a single, patient-specific, clinically actionable result (e.g., score, risk classification, or predictive index) (AMA CPT code set).   

Encounter: Documented direct, face-to-face contact between a patient and a physician (or other authorized provider) for the purpose of ordering or furnishing hospital services for diagnosis and/or treatment (42 CFR 410.2).  

Inpatient: A person formally admitted to a hospital for bed occupancy, generally with the expectation that care will span at least two midnights (42 CFR 412.3).  

Outpatient: A person registered in the hospital or CAH records as an outpatient who receives services directly from the hospital or CAH without an overnight stay (e.g., emergency department, observation, outpatient surgery, lab tests, or X-rays) (42 CFR 410.2).  

Non-patient (referred) laboratory specimen: A specimen submitted to a hospital for analysis from a person who is neither an inpatient nor an outpatient and is not physically present at the hospital (Medicare Claims Processing Manual, Pub. 100-04, Ch. 16, §40.3).  

General rule and variation

• General rule: The DOS is the date the specimen was collected, unless one of the 42 CFR 414.510(b) exceptions listed below apply.
• Variation: If a specimen is collected over a period that spans two calendar days, the DOS is the date the collection ended.

Exceptions to the DOS rule

The following three exceptions, set out at 42 CFR 414.510(b), apply to the DOS rule for either a clinical laboratory test or the technical component of a physician pathology service.

With the exception of the archived-specimen rule described below, which applies regardless of patient status, each of these exceptions applies only when the specimen originates from a hospital inpatient, outpatient, or surgical encounter. A non-patient (referred) specimen that has not been archived originates from none of these, so for such a specimen the DOS is almost always the date of specimen collection.

Exception 1 Tests/services performed on stored specimens

• Stored ≤ 30 calendar days: The DOS is the date the test/service was performed only if all of the following are met:
  • The test/service is ordered by the patient’s physician at least 14 days following the date of the patient’s discharge from the hospital.
  • The specimen was collected while the patient was undergoing a hospital surgical procedure.
  • It would be medically inappropriate to have collected the sample other than during the hospital procedure for which the patient was admitted.
  • The results of the test/service do not guide treatment provided during the hospital stay.
  • The test/service was reasonable and medically necessary for the treatment of an illness.
• Stored > 30 calendar days (archived): The specimen is considered archived, and the DOS is the date the specimen was obtained from storage. This rule carries none of the conditions above and applies to any stored specimen regardless of patient status.

Exception 2 Chemotherapy sensitivity tests/services performed on live tissue

The DOS is the date the test/service was performed only if all of the following are met:

• The decision regarding the specific chemotherapeutic agents to test is made at least 14 days after discharge.
• The specimen was collected while the patient was undergoing a hospital surgical procedure.
• It would be medically inappropriate to have collected the sample other than during the hospital procedure for which the patient was admitted.
• The results of the test/service do not guide treatment provided during the hospital stay.
• The test/service was reasonable and medically necessary for the treatment of an illness.

Exception 3 Advanced diagnostic laboratory tests (ADLTs) and molecular pathology tests

This exception covers a molecular pathology test performed by a laboratory other than a blood bank or center; a test designated by CMS as an ADLT under paragraph (1) of the definition at 42 CFR 414.502; a cancer-related protein-based Multianalyte Assay with Algorithmic Analyses (MAAA); or a specific multianalyte assay with algorithmic analysis separately enumerated in the regulation. The specific tests within this exception are those CMS identifies on its list of applicable HCPCS codes, which is updated quarterly. For any of these, the DOS is the date the test was performed only if all of the following are met:

• The test was performed following the hospital outpatient’s discharge from the hospital outpatient department.
• The specimen was collected from a hospital outpatient during an encounter (both as defined in 42 CFR 410.2).
• It was medically appropriate to have collected the sample from the hospital outpatient during the hospital outpatient encounter.
• The results of the test do not guide treatment provided during the hospital outpatient encounter.
• The test was reasonable and medically necessary for the treatment of an illness.

Date of service by patient status (ADLT and molecular tests)

The DOS depends on the patient’s status and where the specimen was collected:

• Hospital outpatient encounter: If all conditions are met, the DOS is the date the test was performed. Document the date of specimen collection and the date the test was performed.
• Inpatient encounter: The exception does not apply; the DOS is the date of specimen collection.
• Non-patient (referred) specimen: The exception does not apply; the DOS is the date of specimen collection.
  As a result, the same test sent to the same laboratory can have a different DOS depending on where the specimen was collected.

Documentation requirements

Documentation supporting the DOS must appear in the patient’s medical record, such as the pathology or laboratory report, and must include:

• The specimen collection date;
• If the specimen was processed before storage, the place of storage; and
• The date the specimen was removed from storage.
• Date the test was performed, when applicable
   

These elements apply to both inpatient and outpatient encounters.

Quick reference

Date of service is determined first by whether the specimen was collected during a hospital encounter; timing of the test order is only relevant when evaluating specific exceptions. Each exception applies only when all listed conditions are met; otherwise, the general rule (date of specimen collection) controls.

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