Answer: One of the main signs of sickle cell anemia are recurrent episodes of excruciating pain, sometimes known as pain crises. Red blood cells with sickle shapes obstruct blood flow to your joints, belly, and chest, causing pain. The duration and intensity of the pain might range from a few hours to many days.
Explanation: So one way of telling if someone is sick with sickle cell anemia would be if you notice them having pain in their joints, belly, and their chest. Also another way of nowing if they have it is to say what type of pains they are having and where they are.
(Hope this helps! Sorry if it doesn't tho.)