Laboratory Guideline Policy - CAM 235HB

To be considered for reimbursement, all outpatient laboratory claims should be submitted in accordance with:

  • AMA CPT and HCPCS coding and ICD-10 diagnosis coding guidelines.

  • Other laboratory and pathology coding guidelines.

  • All applicable regulatory guidelines.

This policy outlines additional requirements beyond the guidelines listed above that are required for reimbursement. Note that these guidelines are reviewed and updated periodically. 

Technical, Professional and Global Services (TC, 26 modifiers) 

  • Before using the 26 or TC modifiers, verify that these modifiers are allowable with the procedure code.

  • Do not append these modifiers to the procedure code when performing the global service.

Test Performed by a Reference Laboratory

  • When laboratory procedures are performed by a party other than the treating or reporting physician to other qualified health care professional, the procedure must be identified by adding modifier 90 to the claim line.

  • Only independent clinical laboratories may append modifier 90 to indicate that the service was referred to an outside laboratory.

Repeat Testing

  • While treating a patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. Under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91.

  • Modifier 91 may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required.

  • Modifier 91 may not be used when other code(s) describe a series of test results (e.g., glucose tolerance tests, evocative/suppression testing).

Clinical Laboratory Improvement Amendments (CLIA) Waived Testing

  • Laboratory tests that are CLIA-waived must have the QW modifier appended to the procedure code. 

In accordance with S611b of OBRA of 1989, a referring lab can bill for tests performed by a reference lab only if it meets any one of the following exceptions: 

  • The referring laboratory is in or is part of a rural hospital.

  • The referring lab and the reference lab are "subsidiary related." That is:

    • The referring lab is a wholly owned subsidiary of the reference lab.

    • The referring lab wholly owns the reference lab.

    • Both the referring lab and reference lab are wholly owned subsidiaries of the same entity. 

Some procedure codes will not be reimbursed due to their expiration or replacement with more appropriate codes. 

  • AMA drug assay codes 80320 to 80377 are not accepted and will not be reimbursed. Refer to policy CAM 140 for guidelines for submitting G0480 to G0483.

  • Proprietary Laboratory Analyses (PLA) codes will not be reimbursed unless a laboratory policy specifically covers the PLA code.

  • Unlisted codes (81479, 81599, 84999) will not be accepted if a specific Tier 1, Tier 2, GSP or MAAA code exists. 

Reimbursement for genetic panel testing is as follows: 

  • If a procedure code is available for the multi-gene panel test, then this code is to be utilized (i.e., 81442 Noonan spectrum disorders genomic sequence analysis panel).

  • If there is not a specific next generation sequencing (NGS) procedure code that represents the requested test, the procedure may be represented by a maximum of ONE unit of 81479 [unlisted molecular pathology procedure] (i.e., 81479 X 1 should account for all remaining gene testing) OR All genes tested on the panel must be represented by ALL appropriate Molecular Pathology Tier 1 or 2 procedure codes (with exception of 81479 x 1 only being listed once if it appropriately represents more than one gene in the panel).

  • ALL gene tests in the panel must be listed on the request and the rationale for the clinical utility for the gene test must come from the ordering provider.

  • If ALL codes that represent the testing of the panel are not submitted, the test will be denied as not medically necessary due to incorrect coding process, as neither laboratory nor clinical reviewer should assign meaning to incomplete unspecified panel codes.

Genetic Counseling Reimbursement Guidelines

  • Genetic counseling, when required, is considered MEDICALLY NECESSARY ONLY when performed by a provider who is NOT an employee or contractor of the rendering lab. Genetic counseling should be independent of the laboratory rendering the testing to prevent conflict of interest. Genetic counseling documentation consists of written documentation of the counseling elements provided to the member (may include risks, benefits, care guidance and follow-up plans). Any genetic counseling provided, whether a covered benefit or not, will be considered during review of health plan laboratory policy where counseling is a required component.


  1. Centers for Medicare & Medicaid Services, “Medically Unlikely Edits”

  2. American Medical Association, Current Procedural Terminology (CPT®), Professional Edition


  4. CMS Pub. 100-04, chapter 16, section 40.1.1 external link (PDF, 497 KB

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

Coding Section



Code Description



Oncology (hematolymphoid neoplasia), optical genome mapping for copy number alterations and gene rearrangements utilizing DNA from blood or bone marrow, report of clinically significant alternation

  0389U (effective 07/01/2023) Pediatric febrile illness (Kawasaki disease [KD]), interferon alpha-inducible protein 27 (IFI27) and mast cell-expressed membrane protein 1 (MCEMP1), RNA, using reverse transcription polymerase chain reaction (RT-qPCR), blood, reported as a risk score for KD
  0390U (effective 07/01/2023) Obstetrics (preeclampsia), kinase insert domain receptor (KDR), Endoglin (ENG), and retinol-binding protein 4 (RBP4), by immunoassay, serum, algorithm reported as a risk score
  0393U (effective 07/01/2023) Neurology (e.g., Parkinson disease, dementia with Lewy bodies), cerebrospinal fluid (CSF), detection of misfolded α-synuclein protein by seed amplification assay, qualitative
  0394U (effective 07/01/2023) Perfluoroalkyl substances (PFAS) (e.g., perfluorooctanoic acid, perfluorooctane sulfonic acid), 16 PFAS compounds by liquid chromatography with tandem mass spectrometry (LC-MS/MS), plasma or serum, quantitative
  0407U (effective 10/01/2023) Nephrology (diabetic chronic kidney disease [CKD]), multiplex electrochemiluminescent immunoassay (ECLIA) of soluble tumor necrosis factor receptor 1 (sTNFR1), soluble tumor necrosis receptor 2 (sTNFR2), and kidney injury molecule 1 (KIM-1) combined with clinical data, plasma, algorithm reported as risk for progressive decline in kidney function
  0418U (effective 10/01/2023) Oncology (breast), augmentative algorithmic analysis of digitized whole slide imaging of 8 histologic and immunohistochemical features, reported as a recurrence score
  0431U (effective 01/01/2024)

Glycine receptor alpha1 igg, serum or cerebrospinal fluid (csf), live cell-binding assay (lcba), qualitative                                                 

History From 2024 Forward     

01012024  NEW POLICY

05/03/2024 Annual review moved to January 2025. No other changes.

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