What Is a Medically Determinable Impairment for SSDI or SSI?

Medically determinable impairments must be documented by objective evidence from an acceptable medical source.

By , Attorney · Seattle University School of Law
Updated 1/04/2024

In order to qualify for disability benefits—Social Security Disability Insurance (SSDI) or Supplemental Security Income (SSI)—you'll need to show that you have a "medically determinable impairment" that keeps you from working full-time. (Children can qualify for benefits if their medically determinable impairment causes marked and severe functional limitations.)

For both children and adults, knowing what Social Security considers a medically determinable impairment is a key part of making sure your disability application is as strong as possible.

What's the Definition of a Medically Determinable Impairment?

According to the Code of Federal Regulations and Social Security's Program Operations Manual System (POMS)—which provides guidance on making disability decisions—a medically determinable impairment (MDI) "must result from anatomical, physiological, or psychological abnormalities that can be shown by medically acceptable clinical and laboratory diagnostic techniques." (20 C.F.R. 404.1521.)

In plain English, this means that Social Security can't approve disability payments based only on what you tell them about your symptoms. You'll need to "show the receipts," supporting your statements with objective medical evidence that meets a certain quality standard.

What Makes a Medically Determinable Impairment?

Social Security's definitions often adopt terms used by doctors that aren't always well understood by the general public. Breaking down this definition further can give you a clearer picture on how to show Social Security that you have a medically determinable impairment.

What Are Anatomical and Physiological Abnormalities?

Anatomical and physiological abnormalities are any conditions that cause issues with your physical well-being. Anatomical abnormalities are problems with your body's structure, while physiological abnormalities are problems with how your body operates. For example, a malformation of the aorta (a vessel connected to the heart) is an anatomical abnormality, but an irregular heartbeat is a physiological abnormality.

For most people, this is a distinction without a difference. Both anatomical and physiological abnormalities can result in difficulties with physical functioning, and the objective evidence required to demonstrate both types is usually the same.

What Are Psychological Abnormalities?

Psychological abnormalities are those that affect your mental health. Conditions such as depression, anxiety, post-traumatic stress disorder, and traumatic brain injury can make it hard to concentrate, interact with other people, and remember simple instructions.

What Are Medically Acceptable Clinical and Laboratory Techniques?

"Medically acceptable clinical and laboratory techniques" are methods of finding out what's causing your symptoms based on established scientific principles generally considered by doctors to be accurate, useful, and up-to-date. Outdated, fringe, or pseudoscientific practices aren't medically acceptable—for example, measuring your skull to determine that you're prone to depression isn't a valid way to diagnose a mental disorder.

How Do I Provide Evidence of a Medically Determinable Impairment?

Social Security can't just take your word for it that you have a specific health concern. The agency needs to see objective medical evidence, from an "acceptable medical source," that your condition exists.

Objective medical evidence consists of signs, laboratory findings, or both—basically, anything that your doctor can observe or examine.

  • Signs can be thought of as physical manifestations of an underlying condition. For example, if your doctor taps your knee and you don't reflexively kick, that could be a sign that you have nerve damage. Or, being needlessly combative with the doctor could be a sign of an impulse-control disorder.
  • Laboratory findings encompass a wide variety of diagnostic procedures, including medical imaging (such as X-rays, CT scans, and MRIs), blood and urine tests, electrocardiograms (EKGs), the WAIS-IV(a measurement of cognitive ability), and the Snellen eye chart (the vision test with a large "E" on top), among others.

Objective medical evidence doesn't include purely subjective symptoms such as pain or anxiety, where only you can really know how you're feeling. While subjective symptoms have value in determining what functional limitations you have—an important factor in assessing your residual functional capacity—objective evidence is necessary to establish that you have a medically determinable impairment in the first place.

What Is an Acceptable Medical Source?

Acceptable medical sources are providers who Social Security recognizes as having the authority to interpret medical evidence and diagnose disorders within the scope of their knowledge. The list of who can be acceptable medical sources is relatively straightforward (for Social Security):

  • licensed physicians (doctors with an M.D. or D.O. degree—this includes psychiatrists, who have an M.D.)
  • licensed or certified psychologists (doctors with a Ph.D. or Psy.D. degree) at the independent practice level
  • school psychologists, or other licensed or certified professionals with other titles (such as guidance counselors), for impairments of intellectual disability, learning disorders, and borderline intellectual functioning only
  • licensed optometrists, either for all visual disorders or just for measurement of visual acuity and field of vision, depending on what state the optometrist practices in
  • licensed podiatrists, either for foot disorders only or for foot and ankle disorders, depending on what state the podiatrist practices in
  • qualified speech-language pathologists (SLPs) for speech and language disorders only. The SLP must either be licensed by the professional licensing agency in the state where they practice, or be fully certified by the education agency in that state, or hold a Certificate of Clinical Competence in Speech-Language-Pathology from the American Speech-Language Hearing Association
  • licensed physician assistants, only for impairments within their scope of practice (in claims filed on or after March 27, 2017)
  • licensed audiologists, only for hearing and balance disorders within their scope of practice (in claims filed on or after March 27, 2017), and
  • certain licensed nurses, for impairments within the scope of their practice (in claims filed on or after March 27, 2017).

Which Licensed Nurses Are Acceptable Medical Sources?

There are several different titles for nurses who are considered acceptable medical sources. Titles vary according to the state in which the nurse is licensed, but the most common are:

  • Advanced Practice Registered Nurse (APRN)
  • Advanced Practice Nurse (APN)
  • Advanced Registered Nurse Practitioner (ARPN), and
  • Certified Nurse Practitioner (CNP) or Nurse Practioner (NP).

Some states use variations such as:

  • Certified Nurse Midwife (CNM)
  • Certified Registered Nurse Anesthetist (CRNA), and
  • Clinical Nurse Specialist (CNS).

Check with your state's medical regulatory body for the appropriate title to make sure that your treating nurse is an acceptable medical source.

Who Isn't an Acceptable Medical Source?

Any provider who doesn't have the above credentials isn't considered an acceptable medical source. This includes social workers, dentists, physical therapists, acupuncturists, chiropractors, massage therapists, or support staff. While these professionals may help provide insight into your disorder, Social Security can't rely on them to diagnose your condition.

Remember, the significance of acceptable medical sources is for the purpose of establishing that you have a medically determinable impairment. Treatment notes from other sources can be useful in establishing the severity of your impairment and explaining how it limits your ability to function.

For example, your physical therapist can't acceptably diagnose you with degenerative disc disease, but an examination from a physical therapist showing your reduced range of motion might provide a basis for restricting the kinds of jobs you could do.

How Can I Obtain Evidence of My Medically Determinable Impairment?

At the first two steps of the disability determination process, Social Security will gather your medical records based on the information you tell them in your initial application or reconsideration appeal. But after you've requested a hearing before an administrative law judge, you'll most likely have to get the records yourself. It's helpful at that stage to get help from an experienced disability attorney who can review your case file and identify any missing or outdated medical records.

If you do want to gather the evidence yourself, make sure you submit release forms for every provider you're requesting records from. It can take several months before you'll have your medical records in hand, so try to keep your file as current as possible. Social Security can sometimes subpoena your medical records, but because that delays a decision on your case, you should strive to have all the records available to the judge at least five days before your hearing date.

For more information, see our article on what medical evidence is required by Social Security.

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