In the Library of Congress classification system, materials on public health laboratories can be found in the RA 428--RA 428.5 range.
Books on pathology are most often found between RB 1 and RB 214. Clinical pathology and laboratory technique are covered in the RB 37--RB 56.5 range.
If you can't find the materials you need, be sure you contact a librarian to help you with your search.
Basic Anatomy for the Allied Health Professions by 
Clinical Immunology and Serology by 
Critical Thinking in Clinical Practice by 
Exploring Anatomy and Physiology in the Laboratory by 
Histopathology Specimens: Clinical, Pathological, and Laboratory Aspects by 
Mosby's Diagnostic and Laboratory Test Reference by 
Nursing Laboratory and Diagnostic Tests Demystified by 
Pathophysiology by 
