Spayed but could she be in heat?

Question
I adopted a female cat from a shelter.  I had her spayed right away.  That was 5 months ago.  She had been a "meower" prior to the surgery and I thought that would solve the problem.  She continued to meow a lot day and night but now it seems to have gotten even worse.  Is this the season for cats to be in heat?  Could something have gone wrong with her surgery?  I have checked her and I could swear she is in heat now. I had her fixed at an animal birth control clinic that I understand does nothing else but spay and neuter. What do you think?  

Answer
Gloria,

The vet can do a hormone titer test.  This would give you an idea if she was spayed properly or not.  If anything is missed in spaying, the cat could have high hormone levels and display seasoning behavior.  Right now in North America we are heavy into seasons!!!!!  After 5 months, normally, her hormone levels should not be where they could cause her to come into season.

If the hormone levels are higher than normal for a spayed cat, the vet may have to do another spay on her.

Best regards... Norm.