Agent Orange and MGUS: VA Presumptive Claims, Ratings and Back Pay

MGUS is an unusual Agent Orange presumptive condition. VA presumes that qualifying herbicide exposure caused it for service-connection purposes, and then typically assigns a 0% rating. That can make the benefit seem pointless, but it is not.

MGUS, short for monoclonal gammopathy of undetermined significance, is often asymptomatic and may only appear after routine blood work. But it can progress to multiple myeloma or another serious plasma cell disorder, and it can sometimes cause separate conditions that VA can rate.

• MGUS has been an Agent Orange presumptive condition since August 10, 2022. A claimant only has to prove that MGUS actually exists and that the veteran had qualifying herbicide exposure.
• Survivors have special retroactive rights in some cases. A claimant whose earlier DIC claim was denied before MGUS became presumptive may elect to have that claim reevaluated. If the reevaluated claim is granted, the effective date may reach back as though the new presumption had been in effect when the original DIC claim was filed.
• Claims with qualifying herbicide exposure do not need a nexus letter connecting Agent Orange to MGUS. The presumption already supplies that link.
• In Hill & Ponton analyzed Board of Veterans’ Appeals decisions involving MGUS and found that 50.8% were granted, 25.4% were denied and 22% were remanded.

The Agent Orange Presumption for MGUS

Congress added MGUS to the Agent Orange presumptive list through the PACT Act. That means August 10, 2022 (the date the PACT Act was signed into law) is generally the earliest effective date available when service connection for MGUS depends solely on the new PACT Act presumption. An earlier effective date may still be possible under a different theory of entitlement or another applicable effective-date rule.

According to the herbicide-exposure statute 38 U.S.C. § 1116, if a veteran has a confirmed MGUS diagnosis and qualifying herbicide exposure, VA should not require a medical opinion proving that Agent Orange caused the disease. The presumption keeps the veteran from having to turn every claim into an argument over toxicology, plasma cells and decades-old exposure.

Does MGUS Have to Be Severe to Qualify?

MGUS does not need to cause symptoms, require treatment or reach a certain level of disability before the Agent Orange presumption applies. It’s a regulation that helps many veterans who learn they have MGUS by accident. A doctor orders blood work for something else, finds an abnormal protein, runs additional testing and eventually identifies MGUS.

The veteran may feel completely normal even though the diagnosis is medically confirmed, but that doesn’t make the diagnosis irrelevant to VA. If the veteran has qualifying herbicide exposure, MGUS can still be service connected. There is also no rule requiring the condition to appear within a certain number of years after Agent Orange exposure, so a veteran diagnosed decades after military service can still be eligible.

Which Service Qualifies for the MGUS Presumption?

The Agent Orange presumption now reaches well beyond veterans who served on the ground in Vietnam. A veteran who meets the location and date requirements does not have to reconstruct the exact moment Agent Orange exposure occurred. The law presumes the exposure, as long as there is enough evidence to place the veteran within a covered exposure category.

Covered Location	Qualifying Dates
Republic of Vietnam (including territorial waters within 12 nautical miles of shore)	Jan. 9, 1962, to May 7, 1975
Thailand, at any U.S. or Royal Thai base, regardless of job or location on base	Jan. 9, 1962, to June 30, 1976
Korean Demilitarized Zone	Sept. 1, 1967, through Aug. 31, 1971
Laos	Dec. 1, 1965, to Sept. 30, 1969
Cambodia, at Mimot or Krek, Kampong Cham Province	April 16 to April 30, 1969
Guam or American Samoa, including territorial waters	Jan. 9, 1962, to July 31, 1980
Johnston Atoll, or aboard a ship that called at Johnston Atoll	Jan. 1, 1972, to Sept. 30, 1977

C-123 Service

Certain Air Force and Air Force Reserve veterans who repeatedly operated, maintained or served aboard C-123 aircraft that had been used to spray herbicides may also receive presumed exposure. These cases can involve flight records, maintenance histories, assignment records and other evidence showing regular contact with the aircraft.

Blue Water Navy Veterans

Veterans who served offshore of the Republic of Vietnam can receive the same herbicide-exposure presumption under 38 U.S.C. § 1116A. The statute generally extends coverage up to 12 nautical miles seaward of a specifically defined demarcation line off Vietnam. Hill & Ponton’s Blue Water Navy Map can help veterans locate their ship to see if service aboard it is covered by the herbicide presumption.

What Does the Research Say About Agent Orange and MGUS?

The National Academies placed MGUS in its highest Agent Orange evidence category: sufficient evidence of an association. That classification means researchers found enough epidemiologic evidence to support an association between herbicide exposure and MGUS. It does not mean a study can tell an individual veteran exactly why one person developed MGUS while another did not.

One of the most important studies came from veterans of Operation Hand Ranch, the Air Force operation responsible for aerial herbicide spraying during the Vietnam War.

MGUS Incidence in Operation Ranch Hand Veterans

Researchers led by Ola Landgren compared stored blood samples from 479 Operation Ranch Hand veterans with samples from 479 Air Force veterans who did not participate in the spraying missions. MGUS appeared in more than twice as many Ranch Hand veterans (7.1% vs. 3.1%). The study reported an odds ratio of 2.37, meaning the odds of MGUS were substantially higher in the heavily exposed veteran group.

Can Agent Orange Affect Whether MGUS Progresses?

MGUS itself is usually stable, the bigger concern is what happens when it does not stay that way. MGUS can progress to multiple myeloma or another plasma cell disorder. Most veterans with MGUS will never develop multiple myeloma, but the risk does not disappear after diagnosis.

Long-term research has estimated that about 1% of MGUS cases progress in a given year. Kyle et al. 2018 found progression in about 10% of patients by 10 years and 36% by 35 years.

A 2024 VA study by Liu et al. involving 10,847 veterans with MGUS found that veterans in the highest Agent Orange exposure group were more likely to progress to multiple myeloma, with a reported hazard ratio of 1.48.

This is why a 0% MGUS rating can open the door to higher ratings later. For many veterans MGUS may never progress, but for some it becomes the first documented stage of a much more serious plasma cell disease.

How to Win an Agent Orange MGUS Claim

The Agent Orange presumption only solves causation. It does not prove the diagnosis, and it does not prove qualifying service. Those two are the reasons an otherwise straightforward MGUS claim can fall apart.

Get the Lab Work Into the File

MGUS is not a condition a veteran can prove by describing symptoms. In fact, many veterans have no symptoms to describe. The diagnosis comes from laboratory and specialist evidence. A medical note that casually lists “MGUS” may not give VA enough information to understand how the diagnosis was made, so the claim file should include the records that establish the monoclonal protein and the specialist’s diagnosis.

Useful evidence may include:

• Serum protein electrophoresis with immunofixation
• M-protein level
• The type of heavy and light chain identified
• Serum free light-chain ratio
• Bone marrow biopsy results, if a biopsy was performed
• Hematology or oncology treatment records

File MGUS Under Its Full Name

A veteran filing an initial disability compensation claim generally uses VA Form 21-526EZ. The claim should identify “monoclonal gammopathy of undetermined significance (MGUS),” rather than simply “abnormal blood work” or “high protein.” A vague description could send VA looking for the wrong condition or leave the rater unable to match the diagnosis to the Agent Orange presumptive list.

If VA previously decided the MGUS claim and the veteran is seeking readjudication based on the PACT Act or new and relevant evidence, the appropriate filing is generally a Supplemental Claim on VA Form 20-0995 rather than another original Form 21-526EZ.

If another condition is being claimed because MGUS caused or aggravated it, that condition should also be identified clearly and listed in the same application. Hill & Ponton’s guide to VA Form 21-526EZ explains the sections of the form and how to fill them.

Separate MGUS From Multiple Myeloma

MGUS and multiple myeloma are related, but they are not the same diagnosis. MGUS involves an abnormal monoclonal protein without the disease features required for multiple myeloma.

Under International Myeloma Working Group criteria, findings such as high calcium, kidney failure, anemia or certain bone lesions caused by the plasma cell disorder can point toward myeloma rather than MGUS. Both conditions appear on the Agent Orange presumptive list, so the distinction usually does not decide whether herbicide exposure qualifies.

It can, however, determine how VA rates the disease, when the higher evaluation begins and whether the veteran is being compensated for the correct diagnosis. It is also one of the questions that repeatedly sends MGUS cases back to VA for more medical development.

Prove Qualifying Service

Vietnam service may be relatively easy to identify from the DD-214 and personnel file. Other herbicide-exposure locations can require more digging.

Useful evidence may include service personnel records, unit histories, ship deck logs, temporary-duty orders, performance evaluations, buddy statements and prior VA decisions that already conceded herbicide exposure. A prior VA exposure finding can be especially useful because the veteran should not have to re-prove a fact VA already accepted in another claim.

Know When a Nexus Letter Actually Helps

A veteran with qualifying Agent Orange exposure does not need a nexus letter linking Agent Orange to MGUS. Paying for a medical opinion to prove something VA already presumes does not strengthen that part of the claim.

A nexus opinion becomes necessary when the veteran claims that MGUS caused or aggravated another disability, or when the veteran does not fit one of the presumed herbicide-exposure categories and must prove direct service connection instead. In either situation, the opinion needs to explain how the physician reached the conclusion based on the veteran’s actual records, risk factors and medical history.

How Often Does the Board Grant MGUS Appeals?

Hill & Ponton identified 59 Board of Veterans’ Appeals decisions involving MGUS issued from 2021 to 2025, including direct MGUS claims, conditions alleged to have resulted from MGUS, survivor claims and disputes involving ratings or effective dates.

Outcome	Decisions	Share
Granted	30	50.8%
Denied	15	25.4%
Remanded	13	22.0%
Other	1	1.7%

Source: Hill & Ponton analysis of Board of Veterans’ Appeals decisions involving MGUS, 2021-2025.

The Board of Veterans’ Appeals tends to handle the more complicated and disputed cases. Some of the Board appeals that were granted relied heavily on medical reasoning: a hematologist, oncologist or treating physician connected MGUS or another plasma cell disorder to the veteran’s exposure.

Why Does the Board Remand MGUS Claims?

A remand means the Board cannot decide the appeal until VA fixes or develops something first, so the appeal remains alive.

In the MGUS decisions analyzed by Hill & Ponton, the unresolved question generally involved whether the diagnosis was MGUS or multiple myeloma, whether MGUS caused or worsened another disability, or whether the claimed herbicide exposure actually occurred.

Survivor claims followed a similar pattern. When a family argued that MGUS or a disease that developed from MGUS contributed to the veteran’s death, the Board sent the case back for a medical opinion on cause of death before it could decide the appeal.

Why Do MGUS Claims Get Denied?

In some cases, VA did not have competent evidence showing a current MGUS diagnosis. That can happen when the veteran knows a doctor mentioned MGUS, but the hematology records, electrophoresis testing or other diagnostic evidence never make it into the VA file.

Other claims failed because VA could not verify herbicide exposure or because there was no credible medical link for an issue that fell outside the Agent Orange presumption. That problem was especially clear when the only evidence offered was the veteran’s own account of a complex blood disorder. The VA presumption is powerful, but it cannot fill in a missing diagnosis, exposure record or medical opinion when one is required.

How Does VA Rate and Compensate MGUS?

VA rates MGUS at 0% under Diagnostic Code 7712. There is no 10%, 30% or 50% MGUS rating under that code, but multiple myeloma with symptoms can receive a 100% evaluation. The 100% evaluation continues for five years after diagnosis of symptomatic for multiple myeloma, followed by a mandatory VA examination.

Because MGUS and multiple myeloma share Diagnostic Code 7712, progression from MGUS to multiple myeloma can function as an increase.

The effective date of the 100% evaluation is not automatically the date MGUS was originally service connected. Instead, VA applies the effective-date rules for increased compensation, which generally look to when the increase became factually ascertainable and when the veteran filed a claim or intent to file.

The other way to increase compensation is a secondary claim for a separate condition the MGUS caused. Peripheral neuropathy is the most common one. But having both diagnoses does not necessarily mean that MGUS caused the nerve damage.

An abnormal M-protein appears in as many as 10% of neuropathy patients with no other apparent cause, and MGUS itself becomes more common with age. As Chaudhry et al. 2017 explain, the two conditions can therefore appear together by coincidence. A persuasive medical opinion should address other possible causes: diabetes, spinal problems, alcohol use, vitamin B12 deficiency, chemotherapy or other known risk factors. The stronger the medical explanation, the less VA has to guess.

Pathways to Higher Ratings

• Peripheral Neuropathy. MGUS-related peripheral neuropathy is rated under the peripheral nerves schedule. VA looks at the affected nerve and whether the impairment is mild, moderate, severe or complete.
• Kidney Damage. Kidney disease related to MGUS, sometimes called monoclonal gammopathy of renal significance, or MGRS, may be rated under the renal dysfunction criteria. VA may consider laboratory findings such as GFR, proteinuria and whether dialysis is required.
• Anemia. Anemia may receive a separate evaluation under the applicable diagnostic code based on blood counts and symptoms such as weakness, fatigue, shortness of breath or functional limitations.
• AL Amyloidosis or Waldenstrom Macroglobulinemia. If MGUS progresses into AL amyloidosis, Waldenstrom macroglobulinemia or another separately rated disease, VA should evaluate the progressed condition under the appropriate diagnostic code.

How Far Back Can MGUS Compensation Go?

This is where MGUS differs sharply from some older Agent Orange presumptive diseases. The Nehmer rules do not provide retroactive benefits for living veterans with MGUS. When Congress added MGUS to the presumptive Agent Orange list, it limited that special retroactive treatment to survivors.

A living veteran instead falls under the liberalizing-law rules in 38 C.F.R. § 3.114, which generally allow no more than one year of benefits before VA received the claim when the requirements for that earlier date are met.

Two veterans may have the same diagnosis, the same Vietnam service and the same Agent Orange presumption. If one establishes the benefit years earlier than the other, the second veteran may not be able to recover all of the payments lost during the delay.

MGUS becoming presumptive did not create an unlimited path back to the date of diagnosis or military service. Survivors, however, have different retroactive rights.

Compensation for the Surviving Spouses of Veterans with MGUS

Under 38 U.S.C. § 1310, Dependency and Indemnity Compensation may be available to a surviving spouse, child or parent when a veteran dies from a service-connected condition. To win DIC for monoclonal gammopathy of undetermined significance, the disease needs to have played a meaningful role in the veteran’s death.

MGUS by itself can make that difficult because it is often asymptomatic and requires no treatment. The stronger survivor claims tend to involve what the MGUS became or what it caused, such as progression to multiple myeloma, AL amyloidosis, significant kidney disease, nerve damage or another serious plasma cell disorder.

The medical question then becomes whether that service-connected disease caused the death, contributed substantially to it or left the veteran materially less able to survive the condition that ultimately caused death.

A death certificate alone may not answer that question, so a medical opinion addressing the veteran’s complete disease course can become critical. Without a medical opinion addressing cause of death, VA often has to send back the case for additional development.

Can Survivors Get Back Pay from an Older Denial?

Survivors have an important retroactive right that living veterans do not have under the MGUS presumptive change. Because the MGUS Agent Orange presumption applied to qualifying survivors beginning Aug. 10, 2022, a surviving spouse whose earlier DIC claim was denied may be entitled to have VA reconsider that decision under the new presumption.

If the requirements are met, benefits may in some cases reach back to the original survivor claim rather than beginning only when the family asked VA to look at the case again. That makes old DIC decisions worth reviewing carefully because a denial issued before MGUS became an Agent Orange presumptive condition may look very different under the law that applies now.

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Get Help with a Denied Agent Orange MGUS Claim

MGUS claims look simple because the Agent Orange presumption handles causation, but the Board appeals show otherwise. A missing laboratory report, an unverified duty location, confusion between MGUS and multiple myeloma or an incomplete medical opinion can still derail the claim.

Hill & Ponton disability attorneys have successfully represented veterans and their families in VA disability matters for 40 years. If VA denied an MGUS claim, failed to recognize qualifying Agent Orange exposure, disputed the diagnosis or overlooked a condition that developed from MGUS, a free case evaluation can help determine the available appeal options.