Subdural haematomas are diagnosed based on a person's medical history, symptoms and the results of a brain scan.
The doctor assessing you in hospital might suspect you have a subdural haematoma if you recently injured your head and have some of the main symptoms of a subdural haematoma, such as confusion or a worsening headache.
It will also be helpful to know if you take anticoagulant ("blood-thinning") medicine to prevent blood clots, as this can increase your chances of developing a subdural haematoma.
If necessary, a blood test can be carried out to assess your blood's ability to clot.
Sometimes your doctor will want to find out if you have previously been diagnosed with another condition that can have similar symptoms to a subdural haematoma, such as dementia or a brain tumour.
Tests may be done to rule these conditions out.
You'll be examined to see if you have any physical signs of an injury to your head, such as cuts and bruises.
Tests to check how your pupils react to light will be used to check for signs of a brain injury.
The Glasgow Coma Scale (GCS) will also normally be used to check your level of consciousness and help determine the severity of any brain injury.
The GCS scores you on:
If your GCS score suggests there may be a problem with your brain, a brain scan will be carried out.
Read more about the Glasgow Coma Scale on the Headway website
Most people with a suspected subdural haematoma will have a CT scan to confirm the diagnosis.
A CT scan uses X-rays and a computer to create detailed images of the inside of your body.
It can show whether any blood has collected between your skull and your brain.
In a few cases, an MRI scan may be used to check for a subdural haematoma instead.
This is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body.