It means you will need to take thyroid medicine. What has your Dr. told you. Mine was 20 last week so my meds were increased I take Levoxyl. The reason mine went so high in my opinion is because I stopped taking the Levoxyl for a month or so. Felt lousy so had my blood tested and voila! Now I return in 6 weeks for another blood test to find the numbers. Maybe I will stay on the dose or it may need to be adjusted. This was my fault for stopping. They told me they like mine around 2.5
Assuming it's a TSH of 11.8 it suggests hypothyroidism. Would repeat it a few weeks after the first test to confirm before committing to medication. Also need to determine the cause of the abnormal lab -- ie, hashimoto's thyroiditis vs transient thyroiditis vs lab error vs other cause of low thyroid, etc.