Getting the diagnosis right often means more than one test. Here is what each test and scan is, and what it tells your team about your myositis.
Diagnosis usually starts with blood tests, including muscle enzymes such as CK, and a myositis-antibody panel. From there, the tests below fill in the rest: how your muscles and nerves are working, whether the skin, lungs, swallowing, or blood vessels are involved, and which type of myositis you have. Not everyone needs every test. Your team chooses the ones that fit your situation, and because the Centre keeps direct pathways to lung, skin, swallowing, and other services, these are arranged without a fresh set of referrals and waits.
Usually the first step: what is leaking from the muscle, and the immune fingerprints of myositis.
What it is: Simple blood work measuring CK and other enzymes that leak from inflamed muscle, plus general health checks during treatment.
In myositis: Helps confirm the diagnosis, follows disease activity over time, and keeps medications safe. Normal results do not rule myositis out.
Read the full guide →What it is: A blood test for the autoantibodies that travel with different types of myositis.
In myositis: Helps confirm the type, points to organs that deserve a closer look, and guides cancer screening decisions.
Read the full guide →How the muscles and nerves are working, and confirming the type of myositis.
What it is: Electrical recordings from your nerves and muscles, using small skin pads and a fine needle.
In myositis: Shows whether weakness comes from the muscle or the nerve, points to muscle inflammation, and helps choose where to biopsy.
Read the full guide →What it is: A scan that uses a magnet, with no radiation, to image the muscles in detail.
In myositis: Highlights areas of active inflammation and older damage, and helps pick the best muscle to sample.
What it is: A quick, painless bedside scan using sound waves, often done right in clinic.
In myositis: Gives an immediate look at the muscle for inflammation and damage, and can guide a needle to the right spot.
What it is: A small sample of muscle examined under the microscope.
In myositis: Often the clearest way to confirm the exact type of myositis and rule out other muscle diseases.
Read the full guide →Myositis can affect the lungs and the muscles used to breathe, so these are watched closely.
What it is: Breathing tests where you blow into a machine to measure lung capacity and how well oxygen passes into the blood.
In myositis: Screen for and monitor lung scarring (interstitial lung disease) and weakness of the breathing muscles.
What it is: A detailed scan that builds cross-section images of the lungs (a high-resolution CT).
In myositis: The main test to find and follow interstitial lung disease. A CT may also be part of cancer screening in dermatomyositis.
What it is: A quick, simple picture of the lungs and chest.
In myositis: An easy first look at the lungs. A CT gives more detail when something needs a closer look.
When myositis involves the lungs, we work with the Interstitial Lung Disease Clinic at UHN, a key partner in the assessment and management of lung disease related to connective tissue disease and myositis. Their team sees this pattern often, and the route there is already defined, so it does not mean starting a new referral from scratch.
Dermatomyositis and overlap conditions show up in the skin and the tiny vessels of the fingers.
What it is: A magnified, painless look at the tiny blood vessels at the base of your fingernails.
In myositis: Abnormal patterns support dermatomyositis and overlap conditions, and help explain Raynaud’s.
Read the full guide →What it is: A small sample of skin, taken by dermatology and examined under the microscope.
In myositis: Confirms the skin disease of dermatomyositis and tells it apart from other rashes.
Some forms of myositis affect the muscles used to swallow, which needs careful checking.
What it is: An evaluation of how safely you swallow, sometimes with a moving X-ray or a small camera.
In myositis: Checks whether the swallowing muscles are affected, and guides safe eating to keep food and drink out of the lungs.
Read the full guide →What it is: A thin, flexible camera used to look at the throat, food pipe, and stomach.
In myositis: Helps assess swallowing or reflux problems and rule out other causes.
Your team will explain any test you need and answer your questions before it is done.