Mr Leslie has learning disabilities and has developed an irregular heartbeat. He has been prescribed medication for this, but is anxious about having regular blood tests to check his medication levels. His doctor gives him a leaflet to explain: the reason for the tests what a blood test involves the risks in having or not having the tests, and that he has the right to decide whether or not to have the test.
The leaflet uses simple language and photographs to explain these things. Mr Leslie's carer helps him read the leaflet over the next few days, and checks that he understands it. Mr Leslie goes back to tell the doctor that, even though he is scared of needles, he will agree to the blood tests so that he can get the right medication.
He is able to pick out the equipment needed to do the blood test. So the doctor concludes that Mr Leslie can understand, retain and use the relevant information and therefore has the capacity to make the decision to have the test.