Date of Service (DOS) Policy

The Date of Service (DOS) is a required field on all Medicare claim types. A laboratory service may take place over a period of time. That is, for a given laboratory test, the date the physician orders the test, the date the specimen is collected from the patient, the date the laboratory accesses the specimen, the date of the test, and the date results are produced may occur on different dates.

In most cases, the DOS for a laboratory test is the date the specimen was collected, unless certain exceptions are met as set forth in the Code of Federal Regulation (CFR) 414.510(b). For instance, if the physician orders the test at least 14 days following a patient's discharge from the hospital, the DOS is the date the test is performed (instead of the date the specimen was collected).

CMS has subsequently made several revisions to the DOS rules. Additional exceptions were included in 42 CFR 414.410(b)(5) for Advanced Diagnostic Laboratory Tests (ADLTs), molecular pathology tests, and cancer-related protein-based Multianalyte Assays with Algorithmic Analyses (MAAAs) when the specimen is collected during an outpatient encounter. For these specific tests, the DOS must be the date the test is performed, when all the conditions are met.

We recognize that the DOS rules can be administratively challenging for laboratories.

Based on frequent inquiries by laboratory providers we believe there may be uncertainty and confusion about how and when does the "14-day rule" apply, when do exceptions to date of service apply and that "date test is performed" is not defined.

This article clarifies the MACs' approach to processing claims and offers guidance on appropriate documentation to adhere to the DOS rule.

Reference:

42 CFR Chapter IV Subchapter B Section 414.510

Federal Register / Vol. 85, No. 249 / Tuesday, December 29, 2020 / Rules and Regulations: XVIII. Clinical Laboratory Fee Schedule: Revisions to the Laboratory (page 86248)

Date of Service (DOS) for Clinical Laboratory and Pathology Specimens:

The DOS rules for either a clinical laboratory test or the technical component of a physician pathology service are as follows:

General Rule: The date of service (DOS) for clinical diagnostic laboratory tests is the date of specimen collection unless the physician orders the test at least 14 days following the patient's discharge from the hospital. When the "14-day rule" applies, the DOS is the date the test is performed, instead of the date of specimen collection.

Variation: If a specimen is collected over a period that spans two calendar days, then the DOS must be the date the collection ended.

Exceptions: The following three exceptions apply to the DOS rules for either a clinical laboratory test or the technical component of a physician pathology service:

  1. DOS for Tests/Services Performed on Stored Specimens:
    In the case of a test/service performed on a stored specimen:
    1. If a specimen was stored for less than or equal to 30 calendar days from the date it was collected, the DOS of the test/service must be the date the test/service was performed only if:
      • 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; and
      • The test/service was reasonable and medically necessary for treatment of an illness.
        • Inpatient Encounter: Please document the specimen collection date, if the specimen was processed before storage, notification of place of specimen storage along with the date the specimen was removed from storage is required.
        • Outpatient Encounter: Please identify the specimen collection date in the patient's records, if the specimen was processed before storage, notification of place of service of specimen storage along with the date the specimen was removed from storage is required
        • Note: For clarification purposes Date test performed is considered the report date.
      • Note: Documentation of the above is required in the patient's medical records such as the pathology or laboratory report for clinical review purposes.
    2. If the specimen was stored for more than 30 calendar days before testing, the specimen is considered to have been archived, and the DOS of the test/service must be the date the specimen was obtained from storage.
      • Inpatient Encounter: Please document specimen collection date, if specimen was processed before storage, documentation of place of service of specimen storage and date specimen was removed from storage is required.
      • Outpatient Encounter: Please note specimen collection date, if specimen was processed before storage, place of service of specimen storage, documentation of place of service of specimen storage and date specimen was removed from storage is required.
      • Note: Documentation of the above is required in the patient's medical records such as the pathology or laboratory report for clinical review purposes.
  2. DOS for Chemotherapy Sensitivity Tests/Services Performed on Live Tissue:
    In the case of a chemotherapy sensitivity test/service performed on live tissue, the DOS of the test/service must be the date the test/service was performed only if:
    • 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; and
    • The test/service was reasonable and medically necessary for treatment of an illness.
    For purposes of applying the above exception, a "chemotherapy sensitivity test" is defined as a test that requires a fresh tissue sample to test the sensitivity of tumor cells to various chemotherapeutic agents. CMS identifies such tests through program instructions issued to the Medicare Administrative Contractors (MACs).
    Note: These tests will be covered only if deemed reasonable and necessary.
  3. DOS for Advanced Diagnostic Laboratory Tests and Molecular Pathology Tests:
    In the case of a molecular pathology test performed by a laboratory other than a blood bank or center, or a test designated by CMS as an ADLT under paragraph (1) of the definition of an advanced diagnostic laboratory test in 42 CFR 414.502, the DOS must be the date the test was performed only if:
    • The test was performed following a hospital outpatient's discharge from the hospital outpatient department.
    • The specimen was collected from a hospital outpatient during an encounter (as both are 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; and
    • The test was reasonable and medically necessary for the treatment of an illness.
    A "blood bank or center" means an entity whose primary function is the performance or responsibility for the performance of, the collection, processing, testing, storage and/or distribution of blood or blood components intended for transfusion and transplantation.
    • Inpatient Encounter: The laboratory DOS exception does not apply. Use date of specimen collection for date of service.
    • Outpatient Encounter: Document date of specimen collection and date test performed. For clarification purposes: Date Test Performed is considered as the Report Date.
    • Non-Patient Encounter: The laboratory DOS exception does not apply. Use date of specimen collection as date of service.
    • Note: Documentation of the above is required in the patient's medical records such as the pathology or laboratory report for clinical review purposes.

Lab tests subject to the exceptions of DOS policy: schedules

References:

DECISION TREE (Based on DOS utilized for laboratory specimen)

Outpatient Encounter

  1. Was the test ordered within 14 days of discharge?
    • Yes: Use Specimen Collection Date
    • No: Move on to 2
  2. Was the test ordered within 15-29 days of discharge?
    • Yes: Use Report Date (Test Performed)
    • No: Move on to 3
  3. Is the test an ADLT, molecular pathology, cancer-related protein-based MAAA, or described by CPT 81490?
    • Yes: Use Report Date (Test Performed)
    • No: Specimen Stored for greater than or equal to 30 days. Use Date Specimen is pulled from Archive

Inpatient Encounter

  1. Was the test ordered within 14 days of discharge?
    • Yes: Use Specimen Collection Date
    • No: Move on to 2
  2. Was the test ordered within 15-29 days of discharge?
    • Yes: Use Report Date (Test Performed)
    • No: Specimen Stored for greater than or equal to 30 days. Use Date Specimen is pulled from Archive

Definitions

Encounter

Encounters (or visits) are documented face-to-face contact between a beneficiary and provider. Encounter means direct personal contact between a patient and a physician (or other person who is authorized by State licensure law, and, if applicable, by hospital or critical access hospital [CAH] staff bylaws) for the purposes of ordering or furnishing hospital services for diagnosis and/or treatment of the patient.

Outpatient

A person who has not been admitted as an inpatient but who is registered in the hospital or CAH records as an outpatient and receives services (rather than supplies alone) directly from the hospital or CAH, including medical or surgical care, that does not involve an overnight hospital stay. Outpatient care may include emergency department services, observation services, outpatient surgery, lab tests, or X-rays.

Inpatient

A person who has been admitted to a hospital for bed occupancy for purposes of receiving inpatient hospital services. Generally, a patient is considered an inpatient if formally admitted as inpatient with the expectation that he or she will require hospital care spanning at least two midnights and occupy a bed, even if later the patient is discharged or transferred to another hospital and does not actually use the hospital bed overnight

Non-Patient (Referred) Laboratory Specimen

A person that is neither an inpatient nor an outpatient of a hospital but still has a specimen that is submitted for analysis to a hospital even when beneficiary is not physically present at the hospital.

Specimen

Refers to a sample of body fluid or tissue collected for laboratory testing. The DNA that is subsequently extracted from it is then referred to as extracted DNA or a sample derived from the specimen.

Archived Specimen

A specimen stored for more than 30 calendar days before testing. NOTE: extracted DNA specimens must originate from a CLIA-certified laboratory or an equivalent facility.

Clinical Laboratory

A facility for the biological, microbiological, serological, chemical, immunohematological, hematological, biophysical, cytological, pathological, or other examination of human specimens for the purpose of providing information used in the diagnosis, prevention, or treatment of any disease or malformed body member, or used in the general assessment of a patient's health. These examinations also include procedures to determine, measure, or otherwise describe the presence or absence of various substances or organisms in the body. Facilities only collecting or preparing specimens (or both) or only serving as a mailing service and not performing testing are not considered laboratories.

Independent Laboratory

A laboratory that is "independent" of both a physician's office and a hospital. The definition of hospital in this context includes facilities that at a minimum meet the requirements to qualify as an emergency hospital (e.g., maintains clinical records, has a utilization review plan, meets the health and safety requirements found necessary by the Secretary of Health and Human Services)

Qualified Hospital Laboratory

A qualified hospital laboratory is one that provides some clinical laboratory tests 24 hours a day, 7 days a week, to serve a hospital's emergency room that is also available to provide services 24 hours a day, 7 days a week. For the qualified hospital laboratory to meet this requirement, the hospital must have physicians physically present or available within 30 minutes through a medical staff call roster to handle emergencies 24 hours a day, 7 days a week; and hospital laboratory technologists must be on duty or on call at all times to provide testing for the emergency room

Reference laboratory

A Medicare-enrolled laboratory that receives a specimen from another, referring laboratory for testing and performs the test on behalf of that laboratory.

Referring laboratory

A Medicare-approved laboratory that receives a specimen to be tested and that refers the specimen to another laboratory for performance of the laboratory test.

Billing laboratory

The laboratory that submits a bill or claim to Medicare.

Molecular Tests

Laboratory methods that use a sample of tissue, blood, or other body fluid to check for certain genes, proteins, or other molecules that may be a sign of a disease or condition, such as cancer.

Clinical Diagnostic Laboratory Test (CDLT)

Laboratory tests that are paid under the Clinical Laboratory Fee Schedule (CLFS)

Advanced Diagnostic Laboratory Test (ADLT)

A CDLT that is covered under Medicare Part B, is offered and furnished only by a single laboratory, and is not sold for use by other laboratories. To be an ADLT, the test must also meet one of the following criteria (1 or 2):

  1. The test
    1. Is an analysis of multiple biomarkers of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), or proteins;
    2. When combined with an empirically derived algorithm, yields a result that predicts the probability a specific individual patient will develop a certain condition(s) or respond to a particular therapy(ies);
    3. Provides new clinical diagnostic information that cannot be obtained from any other test or combination of tests; and
    4. May include other assays.
  2. The test is cleared or approved by the Food and Drug Administration.

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).

Under arrangements

A provider may have others (in this case laboratories) furnish certain covered items and services to their patients through arrangements under which receipt of payment by the provider for the services discharges the liability of the beneficiary or any other person to pay for the service. In permitting providers to furnish services under arrangements, it was not intended that the provider merely serve as a billing mechanism for the other party. Accordingly, for services provided under arrangements to be covered, the provider must exercise professional responsibility over the arranged-for services. When the hospital obtains laboratory tests for outpatients under arrangements with clinical laboratories or other hospital laboratories, only the hospital can bill for the arranged services.

Last Updated Jun 30 , 2026