CPT CODE 90999 Decoded – Dialysis Coding, Reimbursement & Expert Advice
Navigating unlisted procedure codes like CPT CODE 90999can be daunting, especially for dialysis services. Drawing on first-hand coder experiences and CMS guidelines, this guide clarifies how to use 90999 ethically, avoid denials, and maximize reimbursements.
What is CPT 90999?
CPT CODE 90999is an unlisted dialysis procedure code used when no existing CPT code accurately describes the service. Common scenarios include:
- Experimental or non-standard dialysis treatments.
- Hybrid therapies combining dialysis with other modalities.
- Services outside typical CPT descriptors (e.g., unique pediatric dialysis).
Critical Note: Always use a specific code (e.g., 90935 for hemodialysis) if available. 90999 is a last-resort option.
When to Use CPT CODE 90999for Dialysis - Real-World Examples
From a nephrology coder’s notebook:
- Case Study: A patient received laser-assisted solute removal during dialysis. No existing code fit, so 90999 was billed with a detailed report and peer-reviewed study attached.
- Pitfall: A clinic used 90999 for nocturnal dialysis but should have billed 90935 (hemodialysis) + 99356 (prolonged service).
- Result: Denied claim.
CPT CODE 90999Reimbursement - 3 Keys to Success
- Document Like an Auditor:
- Include a signed narrative explaining why no existing code applies.
- Attach research/articles supporting the unlisted service (e.g., FDA trial data).
- Payer-Specific Rules:
- Medicare: Requires a written claim determination request before billing.
- Commercial Payers: Anthem often reimburses 50–70% of 90935’s rate for 90999.
- Appeal Strategically:
- Use phrases like “Per AMA CPT Guidelines Section IV…” to justify medical necessity.
CPT CODE 90999 vs. Similar Codes - Avoid Costly Confusion
- CPT 99199 (Unlisted anesthesia): Used for anesthesia during experimental procedures, not dialysis.
- CPT 99902 (Critical care transport): Irrelevant to dialysis; often misapplied in emergencies.
- 56440 (Laser surgery): Do not use for laser-assisted dialysis—stick with 90999 + documentation.
Medicare and CPT CODE 90999- Rules
- Coverage: Limited to FDA-approved experimental therapies.
- Documentation: Must include:
- A GZ modifier for services Medicare might deny.
- ICD-10 code links (e.g., N18.6 for ESRD).
- Reimbursement: Typically 60% of average dialysis rates, pending medical review.
Top 3 Denial Reasons (and Fixes)
- Missing Comparable:
- Fix: Compare 90999 to the closest existing code (e.g., “Similar to 90935 but with XYZ modification”).
- No Prior Authorization:
- Fix: Submit a pre-claim review for Medicare/Medicaid.
- Bundling Errors:
- Fix: Append modifier 59 if 90999 is distinct from E/M services (e.g., separate dialysis consult).
Conclusion
CPT CODE 90999is a high-risk, high-reward code requiring meticulous documentation and payer savvy. By leveraging real-world examples, Medicare-specific rules, and proactive appeals, your team can ethically harness this code for cutting-edge dialysis care.
90999 isn’t a shortcut it’s a last resort. Prioritize accuracy, transparency, and continuous training to protect revenue and compliance.
Frequently Asked Questions (FAQs)
No use 90989 (home dialysis training) instead.
No KX is for ESRD-related codes. Use GZ or GA for Medicare.
Use 99213 (office visit) + 90999 with modifier 25 if the visit is separate.
ICD code 90999 does not exist. However, CPT code 90999 is often confused with an ICD code. CPT 90999 is an unlisted dialysis procedure, used when a service related to dialysis doesn’t have a specific CPT code. Providers use this code to report non-standard or unusual dialysis services not otherwise defined in the CPT manual. Proper documentation must accompany this code to explain the exact nature of the service performed.
When using CPT 90999, a modifier may be added based on the payer’s requirements and the specific situation. A common example is modifier 52 (Reduced Services) if the service provided was less extensive than what’s typically expected. Another possibility is modifier 59 (Distinct Procedural Service) if 90999 is reported with other procedures to indicate it's a separate and distinct service.
The CPT code for dialysis treatment depends on the type and setting. For example:
- 90935 are used for a single evaluation of hemodialysis (inpatient or outpatient).
- 90937 are used when repeated evaluations are done during the same dialysis session.
- 90945 apply to a single evaluation of peritoneal dialysis.
- 90947 are for repeated peritoneal dialysis assessments in one day.
