Limited to blood and body fluids visibly contaminated with blood

Fibers can be mistaken for casts on occasion, especially hyaline casts. Fibers, however, are usually thinner and appear less uniform in structure than casts do.
Urinalysis & Other Body Fluids
Which of the following artifacts may be mistaken for casts?

IgE levels are often increased in patients with allergic disease. IgE binds to the membranes of mast cells and basophils, and if specific antigen is present to react with the IgE molecule, degranulation of these cells occurs, releasing histamines, and other substances into the blood or tissues.
Which of the following immunoglobulin classes is chiefly responsible for the degranulation of mast cells and basophils:

Most anticoagulants in blood collectiong tubes prevent clotting by:
Question options:

The red portion of the NFPA diamond represents fire hazards. The fire classification system for NFPA is as follows:
0 - Will not burn
1 - Must be preheated for ignition; flashpoint above 200°F (93°C)
2 - Must be moderately heated for ignition, flashpoint above 100°F (38°C)
3 - Ignition may occur under most ambient conditions, flashpoint below 100°F (38°C)
4 - Extremely flammable and will readily disperse through air under standard conditions, flashpoint below
73°F (23°C)
A laboratory labels its secondary containers of hazardous chemicals using a color-coded system, with a different color representing each different type of hazard. The coding system follows the color-coding used by the National Fire Protection Agency's "fire diamond." What hazard would be represented by the red section on the hazard label?