Nicotine and cotinine tests detect evidence of nicotine in the body. Learn more about when these tests may be used and how to understand your test results.
Osmolality measures the amount of dissolved substances (e.g., sodium, potassium) in blood and urine. An osmolality test and calculated osmolal gap help determine if someone has ingested a toxin or has a water imbalance.
Considering a hair follicle drug test? Learn about how long drugs can be detected in the hair, which drugs can be identified, and how hair testing works.