What is the importance of medical evidence in VA disability claims?

Last Updated: 7/11/2025

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When you file a disability claim with the U.S. Department of Veterans Affairs (VA), medical evidence is the foundation of your case. It is the proof that links your disability to your military service and determines how severe your condition is. Without strong medical documentation, the VA may deny your claim or assign a low disability rating.  Understanding what medical evidence is needed—and how to obtain it—can improve your chances of receiving the benefits you have earned.

It all starts with connecting your condition to your time in service...

What is service connection, and why does it matter?

Service connection is the VA’s way of determining whether your disability is related to your military service. To qualify for VA disability benefits, you must meet three criteria:

1. A current medical diagnosis.
2. Evidence that the condition originated during service, was worsened by service, or is connected to service.
3. A nexus, or medical link, between your current condition and your military service.

Medical evidence plays a critical role in proving each of these elements. If your records fail to establish a service connection, the VA may deny your claim.

What role does medical evidence play in proving service connection?

There are three main ways to establish service connection:

• Direct Service Connection – Requires medical records showing that your condition began or was diagnosed during service.
• Presumptive Service Connection – Applies to conditions that the VA assumes are related to service, such as Agent Orange-related illnesses for Vietnam veterans.
• Secondary Service Connection – Covers conditions caused or worsened by an existing service-connected disability, such as depression resulting from chronic pain.

What happens if my service connection is weak or missing?

If your service medical records do not fully document your condition, you may need to submit additional evidence, such as private medical records, Independent Medical Opinions (IMOs) or buddy statements from fellow service members. Taking proactive steps to strengthen your evidence can prevent unnecessary delays and denials.

Why is the severity of my condition critical to my compensation?

The VA assigns disability ratings in 10% increments based on how much your condition affects your ability to work and perform daily activities. Your medical evidence must clearly demonstrate the severity of your symptoms, treatment history and limitations to ensure an accurate rating.

What types of evidence help establish condition severity?

Your VA disability rating is determined by how severe your condition is and how it affects your daily life and ability to work. The VA relies on medical evidence to assess the extent of your condition and assign an appropriate rating. To receive the benefits you deserve, your medical records should paint a clear and complete picture of your condition, including symptoms, treatments and the impact on your daily activities.

Some of the most valuable types of medical evidence for establishing condition severity include:

• Comprehensive medical records – Your medical history should document symptoms, diagnoses, treatments and how your condition has progressed over time. Detailed physician notes, hospital records and prescribed medications all help demonstrate the impact of your disability.
• Specialist evaluations – If your condition is complex or requires specialized care (for example, post traumatic stress disorder, traumatic brain injury or degenerative neurological disorders), an evaluation from a specialist can provide expert insights into your condition’s severity.
• Diagnostic test results – Objective tests, such as X-rays, MRIs and lab results, provide concrete proof of medical conditions and their progression, strengthening your case for a higher disability rating.

What mistakes can lead to an incorrect VA disability rating?

A low disability rating can mean significantly reduced compensation, leaving you without the financial and medical support you need. Unfortunately, many veterans receive lower ratings due to avoidable errors in their medical evidence or claims process.

Common mistakes that can negatively impact your disability rating include:

• Submitting incomplete or outdated medical records – If your records do not fully document your condition’s severity or lack recent updates, the VA may consider them insufficient.
• Failing to report worsening symptoms – If your condition has deteriorated since your last evaluation, but your medical records do not reflect this, your rating may not be adjusted appropriately.
• Not attending or underpreparing for VA Claims Exams – These exams are also known as Compensation & Pension (C&P) exams and play a significant role in determining your disability rating. Missing the exam or failing to describe your symptoms during the evaluation can result in an underrated condition.

What are the best types of medical evidence for VA disability claims?

The following are the common and effective forms of medical evidence to submit for your claim.

Service Treatment Records (STRs): These document injuries and medical conditions recorded during your time in service. These records serve as primary evidence for direct service connection. If your STRs are incomplete or missing, you can request copies from the National Personnel Records Center (NPRC) or submit alternate evidence, such as buddy statements or private medical records.

VA and Private Medical Records: Both VA healthcare records and private medical records are crucial in demonstrating the long-term effects of your condition. Private doctor statements may provide more in-depth assessments, especially if you have seen specialists outside the VA system.

Independent Medical Opinions (IMOs) and Nexus Letters: An IMO from a qualified expert can be used to clarify complex medical issues. A nexus letter from a doctor explicitly stating that your condition is “at least as likely as not” connected to your military service can significantly strengthen your claim.

VA Claim Exams: These exams (also referred to as Compensation & Pension, or C&P exams) are conducted by VA medical professionals to assess your condition. The examiner’s report heavily influences your disability rating. If the VA claim exam results do not accurately reflect your condition, you can challenge the findings by providing additional medical evidence or requesting a new exam.

Lay Statements: Firsthand accounts from family members, caregivers or fellow service members can provide valuable insight into how your disability affects daily life. These statements can be especially useful when medical records lack details about functional limitations.

What should my documentation include?

Your records should include detailed descriptions of your symptoms, treatments and how your condition affects your ability to work and perform daily activities. If your records lack detail, work with your healthcare provider to ensure complete documentation.

How do I tell whether I need to get a second opinion?

If your initial claim is denied, an IMO or additional expert evaluation can provide critical supporting evidence. You should also consider using an experienced representative such as Allsup Veterans Appeals (AVA). The experts at AVA will know how best to appeal, the requirements to make it successful and the attention needed to carry it through to completion.

How much of a difference does strong medical evidence make?

A well-documented claim increases your chances of approval. Veterans who submit clear, comprehensive medical evidence are more likely to receive benefits than those with incomplete or weak records.  

Strong medical evidence prevents delays, reducing the need for additional requests from the VA. Submitting thorough documentation upfront can result in faster decisions and fewer appeals.

Maintaining up-to-date medical records ensures continued access to VA healthcare and potential rating increases. If your condition worsens, you may qualify for a higher disability rating, increasing your benefits.

What if my claim is denied?

Many claims are denied due to insufficient evidence or procedural errors. If this happens, Allsup Veterans Appeals℠ (AVA) can help.

Allsup Veterans Appeals provides experienced guidance to help you secure the benefits you’ve earned through your service. Since 2012, AVA has delivered VA appeals representation focused on the unique needs of veterans.

Our VA-accredited Claims Agents, some of whom are veterans, understand the VA process. We know what it takes to create an accurate, successful claim.

Working with AVA means you will receive expert guidance, precise submission of your appeal, handling of complex processes, communication with the VA and the support you need