Reddit reviews Textbook of Diagnostic Microbiology (Mahon, Textbook of Diagnostic Microbiology)

I'm not aware of any textbook that contains all the subjects in one, and isn't test prep (question and answer format). That said, I only used ASCP's book (BOC Study Guide), which was not that helpful. These are probably too much information, but if she already knows enough about the clinical laboratory to navigate them, they may be helpful. Particularly if you can find cheap used ones a few editions old. These are the books I used for my clinical theory classes:

Hematology

Hematology Atlas

Clinical Chemistry

Clinical Microbiology

Parasitology

Blood Banking

She may also need one for Urinalysis & Body Fluids, though I have not used this one, just picked it from Amazon.

If nothing else the blood banking one is cheap! Good luck!