CCSD code B1800 – Thymectomy for myasthenia gravis or thymoma

Key takeaways

CCSD code B1800 covers thymectomy for myasthenia gravis/thymoma, so one code applies whether myasthenia gravis, a thymoma, or both led to surgery.

B1800 is the code for open thymectomy, usually through a sternotomy. VATS thymectomy is coded E6200, and robotic thymectomy is coded B1802 or B1803.

Bupa’s February 2026 schedule bands B1800, E6200 and B1802 at Major 5 with a £650 fee, while B1803 sits at Major 4 with £618.

The pre-authorization request should name the planned approach and its code, because a change of approach changes the code on the claim.

Pabau, the practice management platform we build, keeps the authorization reference, operative note and CCSD-coded invoice on one patient record.

CCSD code B1800: Definition and clinical scope

CCSD code B1800 is the procedure code for thymectomy for myasthenia gravis/thymoma, the official descriptor in the CCSD schedule. It covers open removal of the thymus gland when myasthenia gravis, a thymoma, or both are the documented indication.

One code serves both indications. The schedule has no separate thymoma-only thymectomy code, so a patient with myasthenia gravis and a thymoma is billed under B1800 alone. Which condition prompted surgery still matters for the diagnosis codes, but it doesn’t change the procedure code.

The surgical approach does change the code. B1800 is the open thymectomy code, most often performed through a median sternotomy. Thymectomy by video-assisted thoracoscopic surgery (VATS) is coded E6200, and robotic-assisted thymectomy is coded B1802 or B1803.

CCSD is the UK private-sector schedule, separate from NHS OPCS-4 codes and US CPT codes. Insurers including Bupa, AXA Health, Aviva and Vitality use it to process consultant claims. Our CCSD code guides cover the neighboring codes in the same format.

What the procedure involves: Thymectomy for myasthenia gravis or thymoma

Myasthenia gravis (MG) is an autoimmune neuromuscular condition. Antibodies, most often against acetylcholine receptors (AChR), block signals between nerve and muscle. The thymus is implicated in that autoimmune response, and removing it improves or settles the disease in many patients.

The key evidence is the MGTX trial (Wolfe et al., NEJM 2016). It showed that thymectomy plus prednisone outperforms prednisone alone in generalized, AChR-antibody-positive, non-thymomatous MG. Cite it when you support a B1800 claim for MG without a thymoma, or appeal a denial.

A thymoma is a tumor of the thymus, and resection is the standard treatment whether or not the patient has MG. In an open thymectomy, the surgeon removes the gland and the surrounding mediastinal fat that may hold ectopic thymic tissue. The operative note must record how complete the resection was.

Clinical indications for B1800

The indication must be explicit in the pre-authorization request and the correspondence behind it. Insurers query claims where the clinical rationale is missing.

• Generalized MG with AChR antibodies: the best-evidenced MG indication, supported by the MGTX trial. Send the neurologist’s confirmation and the antibody serology with the request.
• Thymoma, with or without MG: a thymoma seen on CT chest is an indication for resection in its own right. An open resection is coded B1800, the same code used for MG.
• Patients aged 18 to 65: MGTX enrolled this age group, so the evidence is strongest here and earlier in the disease course.
• MuSK-antibody-positive MG: the evidence for surgical benefit is weaker than in AChR-positive disease. The request should quote the neurologist’s opinion directly.
• Ocular MG only: thymectomy is generally not indicated. Approval is unlikely without exceptional justification from the treating neurologist.
• Refractory MG despite optimal medical therapy: patients not controlled on anticholinesterases and immunosuppression may be candidates, whatever their antibody status.

How B1800 differs from the VATS and robotic thymectomy codes

Thymectomy has four CCSD codes, and the surgical approach decides which one applies. The indication can be MG or thymoma under each of them. Bupa’s February 2026 schedule, covered in our Bupa CCSD codes guide, lists them as follows.

Bupa’s April 15, 2025 schedule-change notice lists B1802 against B1800, B1803, E6200, E6300 and T1100 as separate codes. That confirms each thymectomy route carries its own code. Code the approach the surgeon used, and code it once. The diagram below traces each route to its code.

Three of the four codes pay the same Bupa fee, so a wrong approach code may not change the amount. It still creates a mismatch with the operative note, and audits catch that. A robotic subtotal thymectomy coded as B1800 also claims a higher category than the B1803 descriptor supports.

Documentation requirements for B1800 claims

Pre-authorization doesn’t settle a claim by itself. These documents should be in the patient’s file before you invoice.

• Operative note: states the open approach, the extent of thymus and mediastinal fat removed, and the intraoperative findings. A bare “thymectomy performed” invites an audit query.
• Neurologist correspondence: confirms the MG diagnosis and that neurology discussed the case before surgery, where MG is an indication.
• Pre-op CT chest report: documents mediastinal anatomy and whether a thymoma is present.
• Pathology report: confirms the histology of the removed tissue, which settles the diagnosis codes when a thymoma is found.
• Conversion note, if relevant: records why a planned VATS or robotic case converted to open surgery. Confirm with the insurer which code applies.
• Pre-authorization reference number: printed on the invoice.

ICD-10 diagnosis codes to pair with B1800

UK private insurers use the WHO ICD-10, not the US ICD-10-CM, so codes such as G70.00 and G70.01 don’t apply. List the diagnosis that drove surgery first, then any second diagnosis.

Pre-authorization: What insurers require for B1800

UK private insurers treat thymectomy as major elective surgery, so pre-authorization is required before the operation. A B1800 claim without a valid pre-authorization reference is the most avoidable denial. Make the authorization check a fixed step before the operation is booked.

1. Send the referral letter to the thoracic surgeon, confirming the diagnosis and the request for a surgical opinion.
2. Attach the neurologist’s letter with the MG diagnosis, antibody status, current medication and the thymectomy recommendation, where MG is an indication.
3. Include the antibody results, or a note explaining why seronegative MG is being treated surgically.
4. Add the CT chest report confirming thymus anatomy and whether a thymoma is present.
5. State the planned approach and its CCSD code: B1800 for open surgery, E6200 for VATS, or B1802 or B1803 for robotic surgery.
6. Ask the insurer how it handles a conversion to open surgery, and keep the answer with the authorization.

Requirements change with each policy year. Check the Bupa code search portal, the Aviva fee schedule, or the Vitality fee finder before you submit.

Billing B1800: Step-by-step claim submission

1. Log the pre-authorization reference number and expiry date against the patient episode before surgery.
2. Check the operative note against the authorized approach, and correct the code if the surgeon used a different route.
3. Attach B1800 to the invoice with the ICD-10 code that drove surgery listed first.
4. Generate an itemized invoice showing B1800 and the payer-specific fee from the loaded fee schedule.
5. Store the operative note, pathology report and neurologist correspondence against the episode for audit.
6. Track claim status and flag any insurer query for the billing team the day it arrives.

Can B1800 be billed with other codes?

Other clinicians bill their own part of the episode alongside B1800. Never bill E6200, B1802 or B1803 with B1800 for the same thymectomy, because each code describes the whole operation by one route.

Common reasons B1800 claims are denied

Denial patterns for B1800 repeat across UK private insurers. Knowing them in advance cuts queries and the cash-flow delays they cause. A denial management process handles the queries that still get through.

• No pre-authorization reference number: the most common avoidable denial. After urgent surgery, request retrospective authorization at once and include a clinical emergency letter.
• Approach code doesn’t match the operative note: B1800 billed for a VATS or robotic thymectomy, or E6200 billed for an open one.
• Change of approach not authorized: a switch from the authorized open approach to a robotic technique may fall outside the original authorization. Tell the insurer before surgery where possible.
• Missing neurologist correspondence: where MG is the indication, a claim backed only by a GP referral and the surgeon’s notes is routinely queried.
• Wrong or missing ICD-10 code: an invoice with no diagnosis code, or a US ICD-10-CM code, triggers an automatic query.
• Vague operative note: a note that omits the approach, the extent of resection or the indication will be queried on audit.

How to appeal a denied B1800 claim

Most UK private insurers have a formal appeal process. They will reconsider a denied B1800 claim when the right clinical evidence arrives.

1. Get the denial reason in writing. The exact reason decides which evidence you need.
2. Gather the clinical documents. Assemble the operative note, neurologist letters, serology, CT report and pathology result.
3. Write a consultant supporting letter. Answer the denial reason point by point. For medical necessity in non-thymomatous MG, cite the MGTX trial.
4. Correct any coding error. If the approach code or ICD-10 code was wrong, send a corrected invoice with the appeal letter.
5. Use the insurer’s formal appeal route. Most insurers want appeals sent to their medical review team, often through the provider portal.
6. Escalate if the first appeal fails. Ask for review at medical-director level when the clinical case is strong.

Coding pitfalls: When not to use CCSD code B1800

• The thymectomy was done by VATS: use E6200, VATS excision lesion of mediastinum (including thymectomy).
• The thymectomy was robotic-assisted: use B1802 for a radical thymectomy or B1803 for a subtotal one.
• The operation was diagnostic only: diagnostic mediastinoscopy is E6300, and diagnostic thoracoscopy with or without biopsy is T1100.
• The tumor invaded beyond the thymus: open resection of an invasive mediastinal tumor has its own code, E6100. Confirm the choice with the insurer at pre-authorization.
• The mass was not thymic: open excision of another mediastinal tumor is E6110, and the robotic equivalent is E6111.
• The target was a mediastinal parathyroid: mediastinal parathyroidectomy with sternotomy is B1690, not B1800.

How Pabau keeps B1800 claims complete from pre-authorization to payment

A thymectomy claim often moves through three places today. There’s the insurer’s portal for authorization, a word processor for the operative note, and a separate billing tool. Each hand-off risks losing the reference number or the approach detail the insurer checks.

Pabau’s private practice billing software keeps those steps on one patient record. The insurer and policy sit on the record, so each invoice routes to the right insurer. Before a claim goes to Healthcode, Pabau checks that details such as authorization codes are in place.

Once sent, each claim moves through visible stages, from submitted to paid. Your team spots a queried B1800 claim the day it stalls. For consultants new to private practice, that structure shortens the learning curve.

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Conclusion

B1800 is settled by two facts, and the indication isn’t one of them. Confirm the surgery is a thymectomy, then confirm it is open. MG, thymoma or both all sit under the same code.

Name the approach in the pre-authorization request and again in the operative note. If the route changes on the day, the code changes with it, and the insurer should hear about it first.

Book a demo to see how Pabau tracks authorizations and CCSD claims for thoracic surgical teams.

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