* When to Visit When your doctor has scheduled lab work for you, or when you get the results back.

* What You Get Succinct reports describing most common lab tests, their purposes, limitations and, sometimes, the meaning of results. A masterfully simple page lets you search by the name of a test if you already know it, or by condition/disease, so you can see what tests you may need.

* What You Don't Get There's a prudish tendency in places to under-specify "reference values" -- the numbers considered normal, low or high. This is often annoying, and in some places patronizing. (See, for instance, Red Blood Count.)

* Who's Behind It, and Why Several professional groups representing the clinical lab industry, led by the American Society for Clinical Chemistry. The site appears to be a public service seeking visibility for the industry. The material is peer-reviewed.

* Commercial Pollution Factor Very low. The sponsors are makers of lab testing equipment, but since a consumer can't choose which equipment to use, there's little risk of self-interested skew.

* Don't Miss The "Screening" search, which neatly describes the tests you ought to be having at various life stages.

-- Craig Stoltz