Lab test pocket reference book

I'm looking for a good pocket reference book for lab tests, procedures etc. There are a few listed on Amazon but they're a bit pricey (in the $30-40 range). If anyone has such a book, what do you use, what do you recommend?
Nursing made incredibly easy has a pocket reference (a true pocket reference, some of them are actually too big to fit into my small pockets). Got it on sale at Borders, awesome book IMHO.

Thanks. I ended up going with Mosby, but an earlier edition so it cost next to nothing. I don't mind that it's 2006, how much did lab tests change in 5 years...