Which tests are which

October 06, 2002|By Jane E. Allen | Jane E. Allen,Special to the Sun

Not everyone feels the need to seek out independent laboratory testing, but it does pay to stay on top of your blood work.

The first thing to know is that results of tests ordered by doctors are part of your medical record and you're entitled to a copy. If you're at risk for, say, high cholesterol, diabetes or prostate cancer, it's a good idea to keep tabs on your numbers.

Sometimes an attentive patient can catch a condition before it becomes advanced, questioning results to which the doctor may have given short shrift.

"If your doctor doesn't have time to go over it with you, you need to find a new doctor," said Dr. Andre Ettinger, an internist at Huntington Hospital in Pasadena, Calif. "When people come in and get a physical with me, we sit down and go over every single number."

The most common blood test is the CBC, or complete blood count, measuring quantities of cells in a given sample of blood, including infection-fighting white blood cells and oxygen-ferrying hemoglobin, and the hematocrit, which measures the percentage of red blood cells. These tests can pick up infection, anemia, leukemia and other disorders.

Most doctors routinely ask the lab to measure several lipids, the technical term for blood fats. These include total cholesterol, as well as high-density lipoprotein ("good" cholesterol), low-density lipoprotein ("bad" cholesterol), and the ratio between the two, which assesses the risk of having a heart attack or stroke. Often, triglycerides are measured as well; when elevated, they're another risk for heart disease.

Glucose levels indicate diabetes risk. Levels of electrolytes, or salts, such as sodium, potassium and chloride, indicate how the heart, liver and kidney are functioning. Levels of creatine, phosphorus and blood urea nitrogen -- or BUN -- can show if the kidneys are working well.

Most laboratories provide, alongside each of your results, a so-called reference range, which is the range of normal readings.

Jane E. Allen is a reporter for the Los Angeles Times, a Tribune Publishing newspaper.

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