As mito can affect each person differently, and many family physicians are unfamiliar with the disease, the process leading to a diagnosis can be long and frustrating. This process usually begins with a family physician sending a referral to a specialist.

Specialists who diagnose mito can include neurologists, metabolic specialists, geneticists, cardiologists, neuro-ophthalmologists or endocrinologists. The type of specialist you see may depend on which part of your body is affected. Specialists will take a medical history, conduct a thorough physical evaluation, measure your strength and endurance, and possibly order a series of specialized tests.

Certain blood tests may be ordered to examine amino acids, acylcarnitines, lactate, or pyruvate levels. Urine tests are often ordered as they can show indicators of reduced mitochondrial function.

A genetic test may be ordered to screen for known, rare and unknown genetic mutations and requires a saliva, blood or muscle tissue sample. A muscle biopsy may be ordered, which involves removing a small piece of muscle tissue. The tissue is treated with a dye that stains the mitochondria, revealing certain mitochondrial enzymes, proteins or muscle cells with excessive mitochondria.

Although receiving a diagnosis can often be a long and uncertain process, knowing exactly which mitochondrial disease you have can help you and your loved ones better understand the disease and plan
a path forward. It can also help you understand the long-term realities of the disease and help your healthcare team create a supportive treatment plan. Getting a diagnosis may ensure other diseases are not overlooked, prevent the wrong treatments from being used, and can stop the need for additional or unnecessary diagnostic testing.

Receiving a genetic diagnosis can identify certain inherited mitochondrial diseases. If this is the case, your specialist may recommend that family members see a genetic counsellor and undergo genetic testing.
A confirmed genetic diagnosis also aids family planning discussions to learn how the inherited disease may affect future children. There are mitochondrial reproductive options, such as pre-implantation genetic diagnosis (PGD) and tests, such as amniocentesis, to determine mitochondrial disease risk.

A genetic diagnosis is also helpful should you ever be interested in enrolling in a clinical trial. Some clinical trial studies may require confirmation of diagnosis through genetic testing to participate.

Other tests may include:  

CT or CAT Scan

Computed (Axial) Tomography 

Using computers and rotating X-ray machines, the CT creates images to provide detailed information about soft tissues, blood vessels, and bones in various parts of the body. 

ECG or EKG

Electrocardiogram 

This fast and simple test records the electrical signals in your heart. Electrodes connect to the ECG machine through wires placed on certain spots on your chest, arms and legs. Specialists will be looking for signs of arrhythmia or cardiomyopathy. 

Echo

Echocardiogram 

An echocardiogram looks for irregularities in the structure of your heart using ultrasound. This test is used to look for signs of cardiomyopathy. 

Electromyography 

This test assesses the health of muscles and nerves. An electrode is inserted through the skin into an affected muscle. The machine records electrical activity of the muscle and can determine whether muscle weakness is caused by the muscle itself or the nerves that control the muscle. An electromyography is often carried out at the same time as a nerve conduction study. 

Genetic Testing 

Genetic testing can determine whether someone has a genetic mutation in the nDNA or mtDNA that causes mitochondrial disease using blood, muscle or saliva samples, as described above. Note: there is no genetic test that completely rules out a genetic condition. 

Labratory tests 

Blood or urine are standard tests used to detect problems with various organs, including the liver and kidney as described above. These tests also look for elevated lactic acid levels, which is common for those living with mitochondrial disease. 

MRI

Magnetic Resonance Imaging 

MRI machines use a magnetic field and computer-generated radio waves to create detailed 3D images of organs and tissues that can be evaluated by a specialist. 

MR Spectroscopy

Magnetic Resonance Spectroscopy 

Using the MRI machine, this test measures levels of certain chemicals within a tissue which may suggest mitochondrial dysfunction. 

Muscle Biopsy 

This procedure involves removing a small sample of muscle, usually from the thigh, as described above. The sample is then treated with a dye. Muscle fibres affected by mitochondrial disease show as a distinct red and have a ragged appearance. 

Nerve Conduction Study 

This test evaluates the ability and speed of nerve impulses and can be used to rule out conditions other than primary mitochondrial myopathies (PMM). 

Neurological Test 

This test uses tuning forks, flashlights and/or reflex hammers to evaluate motor and sensory skills, hearing, vision, speech, coordination, and balance.

Spinal Tap or Lumbar Puncture 

A needle is inserted between two vertebrae to remove a small amount of cerebrospinal fluid (CSF) to measure glucose, protein and/or lactic acid levels. CSF surrounds and protects the brain and spinal cord and abnormal lab values may indicate mitochondrial disease. 

Every patient’s journey is unique. If you suspect mitochondrial disease, ask your health team if they have considered it and explain why you would like it to be considered.