Why Did My Son Need Multiple Blood Tests After a Fever?

Followed up from my sons past appointment with his doctor for him not eating much and losing weight while sick with that fever virus and she decided she wanted to take blood for lab work looking for any underlying problems
Nurses couldn’t find a vein and stuck my lil man in both arms. Then sent us to the hospital for them to have to stick him again! Luckily they were able to get it this time. Lab results came back though and everything checked out well except a low platelet count that we have to go back for next month for more blood 😩😩 my son is going to be terrified of doctors