My cat is really skinny, is that a health problem?

[Jane]

She is a female part simese, that weighs 4 pounds. We found her laying on the side of the rode in the rain. The doctor says nothing is wrong with her, but i have my doubts.

[Charli]

how old does the doc think she is? did he run a fecal test to rule out worms? bloodwork to make sure all her blood levels are normal? if she is a stray, then it may take some time to get her weight up...if she is young, then put her on a kitten diet for extra calories and protein, if she is old, then ask your vet..or consider a second opinion