What Is a Nexus Letter? When You Need One & What It Should Include
- Kristopher Biegel
- Sep 16
- 3 min read
If you are building a VA disability claim, you will see the term nexus letter everywhere. This post explains what is a nexus letter, when you should use one, what makes it persuasive, and the steps to assemble the right records so your claim is ready for review.
What Is a Nexus Letter: quick definition
A nexus letter is a medical opinion that links a current diagnosis to military service.
It answers the causation question using VA language such as at least as likely as not which means a 50 percent or greater probability.
It can also explain aggravation if service made a pre-existing condition worse beyond natural progression.
The author should be a licensed medical professional with appropriate expertise.
When a nexus letter helps most
Direct service connection when symptoms or injuries began during service and your records support continuity.
Secondary service connection when a service-connected condition causes or aggravates another diagnosis.
Service aggravation when a pre-service condition worsened due to service demands or exposures.
Evidence gaps or confusing C&P notes where clear medical reasoning can resolve doubts.
What a strong nexus letter should include
Explicit opinion statement that it is at least as likely as not the condition is related to service.
Diagnosis and clinical context with onset, course, and current status.
Evidence reviewed such as (Service Treatment Records) STRs, VA and private records, imaging, labs, lay statements, MOS details, and exposure history.
Reasoned medical rationale that ties specific facts to accepted medical principles.
Aggravation analysis when relevant, including baseline and how severity increased beyond natural progression.
Provider credentials and signature to establish competence and credibility.
Evidence to gather before requesting a nexus letter
Service Treatment Records and deployment or duty notes.
VA and private treatment records that show continuity.
Imaging, diagnostic tests, and medication history.
Lay or buddy statements that confirm events or symptom timelines.
MOS duties and exposures that explain biomechanics or environmental risk.
Step-by-step process to get yours
Confirm your current diagnosis and list active symptoms.
Organize your packet with labeled files for STRs, imaging, and treatment notes.
Write a one-page timeline of onset, flares, and key care dates.
Request the nexus letter with a clear question about direct, secondary, or aggravation.
Review for accuracy so names, dates, and references match your records.
Common mistakes to avoid
Only stating conclusions without a clear mechanism of causation or aggravation.
Missing baseline when claiming aggravation.
Large gaps in care that are not explained.
Inconsistent dates across records and the letter.
Unorganized uploads that slow review and increase the chance of oversight.
How the nexus letter interacts with a C&P exam
A well-reasoned nexus letter can clarify causation if a C&P opinion is brief or uses the wrong standard.
Consistent terminology between your records, nexus letter, and C&P exam improves credibility.
Bring your timeline and key documents to the exam so details are accurate.
FAQs
Do I always need a nexus letter? Not always. If the evidence already clearly connects your condition to service, a letter may be optional but it can still add clarity.
Who can write a nexus letter? A licensed medical professional with relevant expertise. Credentials and rationale matter more than fancy language.
What if my C&P exam seems unfavorable? A detailed, reasoned nexus letter can address gaps, clarify causation, or rebut assumptions with evidence.
How long should it be? Long enough to explain the logic and evidence, often 1–3 pages with a tight rationale.
Conclusion
A well-crafted nexus letter connects the dots for VA reviewers. By defining what is a nexus letter, gathering targeted evidence, and requesting a clear opinion that states at least as likely as not, you give the rater a simple, credible path to grant your claim.
Ready to move forward? Submit the form on our Order Now page, upload your records using the Document Checklist, and our team will review your packet and draft a focused nexus letter if the evidence supports it.
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