A secondary claim lets you add a new disability rating for a condition caused or aggravated by one you already have service-connected. The legal authority is 38 CFR § 3.310. You don't need a lawyer to file one. You need the right evidence, in the right format, submitted in the right order.
Here's the exact sequence.
Step 1: File Your Intent to File Today
Before you schedule a doctor's appointment, before you call the VA, before you do anything else — file your Intent to File (ITF).
An ITF is VA Form 21-0966. It takes five minutes to submit on VA.gov. Filing it locks your effective date — the date from which your back pay will be calculated. Even if your claim takes eight months to process, your compensation will be calculated from your ITF date, not your decision date.
You have 12 months from your ITF date to submit the formal claim. If you miss that window, you lose the back-pay protection and have to file a new ITF.
File your ITF on VA.gov now — then come back and follow the remaining steps.
Use the Effective Date Visualizer to see exactly what your ITF date protects.
Step 2: Get the Medical Diagnosis on Record
The VA cannot rate a condition that isn't formally diagnosed. Before you file, you need a diagnosis from a licensed medical professional in your medical record.
For most secondary conditions, this means a private doctor visit. VA doctors can diagnose but often won't write the nexus letter you need next — which is why most veterans use a private physician for this step.
What the VA needs to see:
- A current diagnosis that matches the condition you're claiming
- The diagnosis connected to your service-connected primary
- Records showing continuity — the condition didn't appear out of nowhere last week
Common secondary conditions and their diagnostic requirements:
- Sleep apnea: polysomnography report with AHI score
- Hypertension: two blood pressure readings at rest, documented
- Tinnitus: formal audiology evaluation on record
- GERD: physician diagnosis; endoscopy if available strengthens it
- Migraines: headache diary plus physician diagnosis
Step 3: Get a Nexus Letter
The nexus letter is the make-or-break document. It is the medical opinion that legally connects your secondary condition to your service-connected primary.
Your nexus letter must contain the phrase "at least as likely as not." Not probably. Not possibly. Those five exact words — because they reflect the legal standard under 38 CFR § 3.310 (50% probability or higher). Without them, the VA has grounds to deny on nexus alone.
The letter must:
- Be signed by a licensed physician (MD or DO)
- State the specific primary condition (e.g., PTSD, lumbar strain)
- State the specific secondary condition being claimed
- Contain the "at least as likely as not" standard
- Cite the medical rationale — the biological mechanism linking the two
Our free Nexus Letter Templates cover 25+ conditions. Print the relevant one, bring it to your doctor, and ask them to review, modify, and sign it on their letterhead.
Step 4: File the Formal Claim on VA.gov
With your diagnosis documented and your nexus letter in hand, you're ready to file.
Go to VA.gov → File a Claim → Start VA Form 21-526EZ.
Key fields for secondary claims:
- Condition: Enter the secondary condition you're claiming (e.g., "Obstructive Sleep Apnea")
- Cause: Select "Secondary to another condition" and identify your service-connected primary
- Evidence: Upload your diagnosis records and your nexus letter in the same submission
Do not mail anything. Upload directly on VA.gov so you have a digital timestamp.
After submission, you'll receive a confirmation with a claim number. Average processing time is 138 days. Your back pay runs from your ITF date.
Step 5: Prepare for the C&P Exam
After you file, the VA will schedule a Compensation & Pension (C&P) exam. This is a medical examination conducted by a VA-contracted examiner who will evaluate your condition and produce a DBQ (Disability Benefits Questionnaire) that becomes part of your record.
The C&P exam is not a doctor's appointment. The examiner is not there to treat you. They are documenting what they observe to support the VA's rating decision. How you present your symptoms on this day affects your rating.
What to do before the exam:
- Review your nexus letter so you know exactly what medical relationship your doctor established
- Document your worst symptom days — bring logs if relevant (headache diary, CPAP compliance data)
- Know your primary condition's service-connected status cold
What to say:
- Describe your worst days, not your average days
- Don't minimize — the VA rates what you report
- Connect your symptoms to the primary condition when the examiner asks
Our C&P Exam Prep Checklist has condition-specific prep for PTSD, sleep apnea, hypertension, migraines, ED, tinnitus, and more.
Step 6: Read Your Decision Letter
The VA will mail you a Rating Decision. It will either grant or deny each condition you filed. Read it carefully.
If denied, the letter will state the reason. Common denial reasons for secondary claims:
- No nexus (the letter didn't meet the legal standard)
- No diagnosis on record at time of claim
- The examiner produced a negative DBQ
- Insufficient medical rationale in the nexus letter
A denial is not the end. You have three options: Supplemental Claim (new evidence), Higher-Level Review (different rater, no new evidence), or Board of Veterans' Appeals (BVA). See our denial response guide for the full decision tree.
What to Do Right Now
- File your ITF on VA.gov — five minutes, free, locks your date
- Use the Condition Finder to confirm what you're eligible to claim
- Get the relevant Nexus Letter Template to bring to your doctor
- Calculate your potential back pay so you know what's at stake