Service Connection: The Three Things Every VA Claim Must Show
Every VA disability decision — grant or denial — is built from three findings: a current disability, something that happened in service, and a link between them. Knowing which element a denial rejected is the first step in answering it.
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The three-element framework comes from Caluza v. Brown and still structures every VA service-connection decision. Most denials reject exactly one element — and the response that fits depends entirely on which one. This center explains the elements, the four routes to establishing them, and what a review of a denied claim looks at.
The three elements, in plain language
1. A current disability
A present-day diagnosed condition — or, in some frameworks, present-day functional impairment. A past injury that fully resolved, or symptoms without a diagnosis, usually cannot anchor a claim.
2. An in-service event, injury, or disease
Something documented or credibly shown to have happened in service: an injury, an illness, an exposure, or the onset of symptoms. Service treatment records, personnel records, and lay evidence can each play a role.
3. A nexus between the two
Competent evidence linking the current disability to the in-service element. This is where most denials land — and where medical opinions, continuity of symptoms, and secondary theories do the work.
For a deeper walkthrough, read the Caluza triangle explained.
Four routes to service connection
Direct service connection
The condition began in, or was directly caused by, service. The classic three-element path.
Secondary service connection
A new disability caused or aggravated by an already service-connected condition — or, after Spicer v. McDonough, by treatment for one. See the Spicer Resource Center for the full framework.
Presumptive service connection
For certain exposures and diseases — Agent Orange, burn pits under the PACT Act, Gulf War illness, radiation — VA presumes the service link when service and diagnosis criteria are met. No nexus opinion is required.
Aggravation of a pre-existing condition
A condition that predated service can be service-connected to the extent service made it permanently worse beyond its natural progression.
When a denial may be worth reviewing
None of these establish entitlement on their own. They are the patterns that make a closer look reasonable.
- Your claim was denied for a missing element — no current diagnosis, no documented in-service event, or no nexus.
- The denial says 'not related to service' but never explains what evidence was weighed.
- A nexus opinion in your file says 'related to' or 'associated with' service without explaining the reasoning.
- You have a presumptive-condition diagnosis and qualifying service, but were denied anyway.
- A secondary condition — caused or worsened by a service-connected disability — was never claimed or never addressed.
- Your service records are incomplete, and you have lay or other evidence that could fill the gap.
- You are not sure which element of your claim the denial actually rejected.
What Oakridge Claims reviews
Guides in this center
- The Caluza triangle explainedThe three elements every service-connection claim must show.
- Why VA claims are deniedThe denial reasons VA uses most, and what each one means.
- Denied for no nexusWhat 'no link to service' means and what evidence answers it.
- Denied for no in-service eventOptions when service records do not document the event.
- What is a nexus letter?What a medical opinion must actually say to carry weight.
- Who can write a nexus letterWhich clinicians can provide competent medical evidence.
- PACT Act presumptivesConditions presumed connected for qualifying toxic exposure.
- Agent Orange presumptivesThe herbicide exposure list and its service requirements.
Service connection — frequently asked
- What are the three elements of service connection?
- A current disability, an in-service event, injury, or disease, and a nexus connecting the two. The framework comes from Caluza v. Brown, and every VA service-connection decision is built from those three findings — most denials reject exactly one of them.
- What is a nexus, and how do I prove it?
- A nexus is competent evidence — usually a reasoned medical opinion — linking the current disability to service. What carries weight is the explanation: the opinion should address the record and the reasoning, not just state a conclusion. Continuity of documented symptoms since service can also support the link.
- What if my service records don't show the injury?
- A claim does not automatically fail. Lay statements from you and those who served with you, post-service treatment records showing early symptoms, and circumstantial evidence can establish an in-service event, and combat service carries a relaxed evidentiary standard under 38 U.S.C. § 1154(b).
- What is the difference between direct, secondary, and presumptive service connection?
- Direct means service caused the condition. Secondary means an already service-connected condition — or treatment for it — caused or aggravated a new one. Presumptive means VA assumes the service link for listed exposures and diseases when the service and diagnosis criteria are met, with no nexus opinion required.
- VA denied my claim. Which element did I lose on?
- The rating decision's reasons and bases section must say. Denials for 'no current disability,' 'no in-service event,' and 'no nexus' call for different responses — the first step in any review is reading that language precisely.
- What does a review cost, and does it commit me to anything?
- The consultation is free and does not create an agent-client relationship. Oakridge Claims decides whether it can offer representation only after reviewing the facts and procedural posture of a case. Filing independently, or with a free accredited Veterans Service Organization, always remains an option.
Get your denial reviewed
Bring your rating decision and, if you have them, your service treatment records and any examination reports. We will read the denial element by element and explain what the record supports — and when it does not support further action, we will say so.
Important: Oakridge Claims evaluates potential representation only after reviewing the facts and procedural posture of a case. Submitting information does not create an agent-client relationship. Veterans may seek free assistance from VA-accredited Veterans Service Organizations.
Authorities
- 38 U.S.C. § 1110 — basic entitlement to service connection.
- Caluza v. Brown, 7 Vet. App. 498 (1995) — the three-element framework.
- 38 CFR § 3.303 — principles relating to service connection.
- 38 CFR § 3.310 — secondary service connection, including aggravation.
- 38 CFR §§ 3.307–3.309 — presumptive service connection.
Disclaimer: Oakridge Claims is a private business and is not affiliated with, endorsed by, or operated by the U.S. Department of Veterans Affairs. No specific outcome, rating, or approval can be guaranteed — results depend on the individual facts of each case and applicable law.