Biological materials:
(1) bacteria, from abscesses or colonic contents
(2) malignant cells
(3) fat
(4) gastric or pancreatic fluids
(5) amniotic fluid
(6) hormones produced in tumors (pheochromocytoma)
(7) red cells from a patient with an unstable hemoglobinopathy (sickle cell disease, etc.)
(8) tissue and fibrin fragments
Chemicals:
(1) methylmethracrylate or other orthopedic cements
(2) clotting agents (microfibrillar products, sponge or fabric materials, topical fibrin)
(3) topical antibiotics in lavage fluids (Bacitracin, Neomycin, Polymyxin)
(4) topical antimicrobial agents in lavage fluids (betadine, alcohol, hydrogen peroxide)
(5) water (hypotonic and can lyze red cells)
(6) air
Prevention is the best solution, with care taken during aspiration to exclude fluids containing contaminants. Filtration and washing may remove some of the contaminants, but heavily contaminated blood may not be usable.
