Claim Raven explanation
What this means
When service aggravated a preexisting disability, this rule addresses how VA calculates the compensable degree of disability. It generally concerns the increase beyond the level that existed when you entered service.
A deduction requires the earlier degree to be ascertainable in rating-schedule terms. The rule also contains exceptions, including where the current disability is total. This is a rating calculation issue after the service-aggravation question has been addressed.
How this helps your claim
If your award subtracts a pre-service percentage, inspect the evidence supporting that specific number. A statement that a condition existed before service does not by itself establish a measurable rating percentage at entry.
What to check in your records
Use your decision, examination reports, and relevant records to check the following points.
- Find the entrance examination and evidence of actual impairment before service.
- Check the rating code and calculation used for any deduction.
- Verify whether VA explained why the pre-service degree was ascertainable and whether an exception applied.
Understand the starting level used in the deduction
A decision applying a preservice deduction should explain both the current evaluation and the earlier degree of disability it subtracts. The earlier degree must be considered in rating terms, not simply inferred from the fact that symptoms existed before service.
Compare the entrance evidence with the diagnostic criteria used in the calculation. If the earlier level cannot be ascertained, read the regulation's treatment of that situation. Keep the service-aggravation finding separate from the later arithmetic so you can identify whether the disagreement concerns entitlement or the amount evaluated.
Does any preexisting diagnosis justify subtracting a percentage?
Not by itself. The rule addresses an ascertainable degree of disability and includes exceptions. A diagnosis identifies a condition; it does not necessarily establish a particular preservice rating level. The decision's evidence and calculation should show how the stated deduction follows the applicable provision.
Official regulatory text
38 CFR § 3.322
eCFR snapshot: September 3, 2026. Layout and spacing are adapted for reading. The full section and its tables are included below.
§ 3.322 Rating of disabilities aggravated by service.
(a) Aggravation of preservice disability. In cases involving aggravation by active service, the rating will reflect only the degree of disability over and above the degree of disability existing at the time of entrance into active service, whether the particular condition was noted at the time of entrance into active service, or whether it is determined upon the evidence of record to have existed at that time. It is necessary to deduct from the present evaluation the degree, if ascertainable, of the disability existing at the time of entrance into active service, in terms of the rating schedule except that if the disability is total (100 percent) no deduction will be made. If the degree of disability at the time of entrance into service is not ascertainable in terms of the schedule, no deduction will be made.
(b) Aggravation of service-connected disability. Where a disease or injury incurred in peacetime service is aggravated during service in a period of war, or conversely, where a disease or injury incurred in service during a period of war is aggravated during peacetime service, the entire disability flowing from the disease or injury will be service connected based on the war service.
Cross References:
Principles relating to service connection. See § 3.303. Aggravation of preservice disability. See § 3.306.
[26 FR 1583, Feb. 24, 1961]
Related references
- 38 CFR § 3.303: VA service connection explained
- 38 CFR § 3.306: VA aggravation of a preexisting condition
- 38 CFR § 4.1: What a VA disability rating measures
- 38 CFR § 3.159: VA duty to assist: records and examinations
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