My Medical Practice Laboratory: Do I Need a Chemistry Analyzer?

What does a chemistry analyzer analyze?

Chemistry tests fall into two broad categories, routine (also called general) and immunochemistry. This article will address routine chemistry testing in a medical practice laboratory and the next installment in this series will cover immunochemistry testing.

Routine chemistries encompass those tests that are measured by any of four methods:

1. Mixing serum or plasma with chemicals that create color when they react with whatever is being measured.
2. Measuring the effects of enzymes on substrates.
3. The use of Ion Selective Electrodes (to measure electrolytes like sodium and potassium.)
4. Nephelometry, which is creating precipitates that cause cloudiness and measuring that cloudiness (used much less frequently used than the other three methods.)

The routine chemistry tests that are most often ordered in a physician office lab (POL) are those in these CPT-defined test panels:

• Comprehensive Metabolic Panel (14 tests)
• Basic Metabolic Panel (8 tests)
• Hepatic Function Panel  (7 – 9 tests)
• Lipid Panel (4-6 tests)

The most commonly ordered individual tests are glucose, potassium, and total cholesterol.

Design differences in chemistry analyzers

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