CCSD Code 0035G: CD279 (PD-1) mutation analysis billing guide

Key Takeaways

CCSD Code 0035G is the UK private-healthcare diagnostic code for CD279 (PD-1) mutation analysis performed on a blood sample, used to assess the immune checkpoint pathway relevant to cancer immunotherapy.

0035G sits in the CCSD Diagnostic Schedule, not the Procedural Schedule. Load it into the diagnostic charge section of your billing system, never the procedure code table.

Bupa, AXA Health, Aviva, Vitality, Allianz Care, WPA, Cigna, and Healix all base reimbursement on CCSD codes, but each insurer sets its own fee for 0035G and its own pre-authorisation rules.

Pabau’s claims management software supports CCSD diagnostic code submission via Healthcode, linking the blood test result to the clinical record before the claim goes out.

Most billing errors on CCSD Code 0035G come from a single mix-up: treating a blood-based genetic test like a surgical or clinical procedure. CD279 (PD-1) mutation analysis is a molecular pathology test run on a blood sample, and how you classify it in your billing system determines whether the claim pays or bounces.

For practices moving from NHS to private practice and encountering CCSD diagnostic codes for the first time, this distinction matters from the first claim.

This guide covers the definition, clinical context, documentation requirements, and insurer guidance for CCSD Code 0035G. It is written for private practice billing staff, laboratory liaison teams, and clinicians ordering PD-1 pathway testing ahead of or during immune checkpoint inhibitor treatment.

CCSD code 0035G: Definition and clinical description

CCSD Code 0035G describes CD279 (PD-1) mutation analysis carried out on a blood sample. CD279 is the cluster-of-differentiation name for PD-1 (programmed cell death protein 1), an inhibitory receptor expressed on activated T cells and encoded by the PDCD1 gene.

Testing looks for mutations or variants in this gene from DNA extracted from a peripheral blood sample, rather than from a tumour biopsy.

The code sits within the CCSD Diagnostic Schedule, maintained by the Clinical Coding and Schedule Development Group for UK private healthcare billing.

As with all codes in the Diagnostic Schedule, the exact billable narrative for 0035G is held in the restricted schedule at ccsd.org.uk; billing staff with registered access should confirm the current wording before raising a claim, since CCSD revises narratives through its periodic bulletin process.

The CCSD Technical Guide (October 2025) sets out the business rules governing how diagnostic codes such as 0035G are structured and interpreted.

Code classification: Diagnostic, not procedural

This is the single most common source of rejected claims for this code. Per the CCSD FAQs, diagnostic codes do not constitute procedures and should never be loaded into a procedure code table. 0035G belongs in the diagnostic charge section of your billing submission, separate from any consultation or procedural codes on the same claim.

• Code type: Diagnostic
• Schedule: CCSD Diagnostic Schedule
• Clinical category: Molecular pathology / immuno-oncology biomarker
• Specimen type: Blood (peripheral venous sample)
• Analyte: CD279 (PD-1) gene (PDCD1) mutation analysis

Clinical context: Why CD279 (PD-1) mutation analysis matters

PD-1 is an immune checkpoint receptor. When it binds its ligand PD-L1, it dampens T-cell activation, a mechanism the body normally uses to limit inflammation but which tumours co-opt to evade immune attack. Checkpoint inhibitor drugs such as pembrolizumab and nivolumab work by blocking this interaction, restoring the T-cell response against cancer cells.

CD279 (PD-1) mutation analysis from blood is used as a precision-oncology biomarker alongside this treatment pathway. Germline variants in the PDCD1 gene, identified from blood-derived DNA, have been associated with differences in survival outcomes for patients on anti-PD-1 monotherapy, which is why clinicians increasingly request this analysis before or during checkpoint inhibitor treatment rather than relying on tumour histology alone.

A 2021 study on metastatic melanoma, for example, linked a specific PDCD1 germline variant (rs2227981) to lower three-year overall survival on anti-PD-1 monotherapy.

Conditions and scenarios where CD279 (PD-1) testing is requested

• Melanoma – baseline biomarker workup before starting anti-PD-1 therapy
• Non-small cell lung cancer (NSCLC) – alongside PD-L1 tumour testing when checkpoint inhibitor treatment is being planned
• Renal cell carcinoma and Hodgkin lymphoma – immunotherapy candidacy assessment
• Suspected treatment resistance or hyperprogression on an existing checkpoint inhibitor
• Rare immune dysregulation presentations where a PDCD1 defect is part of the differential diagnosis

Documentation requirements for CCSD Code 0035G

Private insurers assess diagnostic claims against the records submitted with them. Incomplete records are the leading reason 0035G claims get queried after filing. Practices also subject to Care Quality Commission inspection should note that this documentation overlaps closely with CQC evidence requirements; a CQC inspection checklist helps align billing and regulatory records in one workflow.

Core documentation checklist

• Clinical reason: A documented indication linking the test to a checkpoint inhibitor treatment plan, or to suspected resistance/hyperprogression
• Requesting clinician: Name and GMC number of the oncologist, immunologist, or specialist who ordered the test
• Specimen type and collection date: Blood sample, with venepuncture date recorded
• Laboratory report: The molecular pathology report confirming the CD279 (PD-1) mutation analysis result
• Insurer approval reference: Pre-approval number where the insurer requires it
• Patient policy details: Membership number, insurer name, and policy type confirmed at registration

Capturing this at the point of care rather than retrospectively at billing time avoids most rejections. Digital intake forms that log specimen type and collection date automatically close one of the more common omissions in this checklist.

For practices that already run structured intake for other blood-based panels, a similar approach to something like an at-home cholesterol test record shows how consistent specimen documentation across different blood tests reduces admin time at claim stage.

Pre-authorisation: The key variable by insurer

Pre-approval requirements for molecular pathology tests vary widely across UK private insurers. Some require prior approval for genetic and biomarker testing ahead of immunotherapy; others process the claim after the fact. Billing staff should never assume pre-approval is unnecessary – verify with each insurer before the blood sample is sent for analysis.

Manage CCSD diagnostic claims without the manual overhead

Pabau gives UK private practices a single platform for clinical documentation, digital consent forms, and claims management, connecting blood test results directly to Healthcode-ready submissions.

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Which insurers recognise CCSD Code 0035G?

CCSD does not set fees for Code 0035G; it publishes the code and narrative, while each insurer sets its own payment rate. The major UK private medical insurers that base reimbursement on CCSD codes are Bupa, AXA Health, Aviva, Vitality, Allianz Care, WPA, Cigna, and Healix. The table below summarises how each approaches CCSD-coded diagnostic claims.

Fee amounts for 0035G are not fixed across insurers. Each payer negotiates its own diagnostic fee schedule, and recognised providers may see different rates depending on their individual recognition agreement. Never quote a patient a fixed reimbursement figure based on what one insurer pays; always check the current published schedule for the specific insurer involved.

Common billing errors with CCSD Code 0035G

The following errors appear regularly in CCSD diagnostic code claims across UK private practices. Clear pre-filing checks prevent most of them.

• Loading 0035G into the procedure code table: This submits the code under the wrong schedule section and triggers rejection. Diagnostic codes live in the diagnostic charge section only
• Confusing PD-1 (CD279) blood testing with PD-L1 tissue testing: These are different biomarkers on different specimen types. Documentation must clearly support a blood-based PDCD1 gene analysis, not a tumour IHC result
• Missing molecular pathology report: Submitting the code without the matching lab result attached, or available on request, exposes the claim to audit challenge
• No clinical indication in the notes: A CD279 (PD-1) result without a documented link to an immunotherapy treatment plan or resistance workup is unlikely to pass a medical review query
• Submitting without pre-approval: Where the insurer requires prior approval for genetic or biomarker testing, submitting without it results in a non-payment decision rather than a delay
• Incorrect specimen documentation: Failing to record that the sample was blood, not tissue, when other biomarker codes appear on the same claim

Related CCSD diagnostic codes

CCSD Code 0035G often appears on a claim alongside other molecular and biomarker diagnostic codes, particularly in oncology and immunology billing. CCSD Code 0002T (Immunoscore) is another immuno-oncology diagnostic code worth cross-checking when a patient’s workup includes multiple biomarker panels, and CCSD Code 0002C (Neurofilament Light Chain) illustrates the same blood/CSF specimen documentation principle for a different biomarker.

Two other CCSD diagnostic codes with a “G” suffix, CCSD Code 0021G and CCSD Code 0025B, follow the same login-gated narrative structure as 0035G. CCSD Code 0019B (Alpha subunit test) is a further example of a blood-based diagnostic code with its own insurer recognition quirks.

Checking the live schedule for all codes on a claim, rather than relying on memory of a previous submission, is the single most effective habit for reducing narrative-mismatch rejections. Our full procedure codes hub and diagnostic codes hub cover the wider CPT, HCPCS, ICD, and CCSD reference library.

How Pabau supports CCSD diagnostic billing for UK private practices

Billing a molecular pathology test like CD279 (PD-1) mutation analysis involves the same administrative chain as any CCSD diagnostic claim: confirming insurer recognition, capturing specimen and clinical documentation, obtaining pre-authorisation where required, and submitting cleanly via Healthcode. For a single oncology or immunology-focused practice, that load is manageable; across a multi-specialty group handling several insurer panels, it compounds quickly.

Pabau’s claims management software lets UK private practices attach diagnostic codes to the appointment record, store the requesting clinician’s details and the specimen collection date against that same record, and generate Healthcode-ready claims without re-entering data by hand.

Practices weighing the benefits of running a private practice alongside NHS commitments, including those managing private GP referral pathways, benefit from having the clinical and billing record in one place.

Practices meeting mandatory compliance requirements and managing patient data under the UK GDPR compliance checklist will find that an integrated clinical and billing record also simplifies audit evidence, since molecular pathology results, consent, and claim history sit in a single system.

The wider picture for running UK private practice operations, including billing workflow alongside scheduling and staff management, is covered in the guide to private practice management.

Conclusion

CCSD Code 0035G bills CD279 (PD-1) mutation analysis performed on a blood sample, a molecular pathology test that supports checkpoint inhibitor treatment decisions in oncology and immunology.

Getting it right means loading it as a diagnostic code rather than a procedure, documenting the blood specimen and clinical indication clearly, confirming insurer recognition and pre-authorisation, and pairing it with the correct laboratory report before submission.

Pabau’s claims management platform connects clinical documentation directly to billing submissions, reducing the manual checking that causes most CCSD diagnostic code errors. To see how it works for UK private practices handling molecular pathology and immuno-oncology billing, book a demo.

Continue your research

Need a full reference for Bupa CCSD codes? Bupa CCSD codes: complete guide for UK clinics covers the full schedule with practical billing guidance for UK private providers.

Managing compliance alongside billing in your private practice? CQC inspection checklist walks through the documentation CQC inspectors review, including clinical procedure and billing records.

Looking at the broader picture of UK private practice operations? Private practice management covers the software tools that reduce administrative overhead across scheduling, billing, and patient management.

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