Most laboratory tests are prescribed by physicians or required by companies. Unlike in Japan, Indonesians are not fully aware of preventative medications. Hence, patients are often left unexplained on why should they take certain lab tests. Knowledge about lab test does not eliminate our needs of doctor, for sure. However, as Charles Bukowski said, "the problem with the world is that the intelligent people are full of doubts, while the stupid ones are full of confidence." Know what doctors told us to do, in this multi-million lab industry, at least, shapes us to be more critical about their decisions upon us.

In general, clinical laboratory tests are classified based on their sample. The type of sample dictates the information that physicians or analysts reagents can gather. For example, hematology test utilizes blood sample to know patient's amount of leucocyte, erhytrocyte, and platetet, meanwhile urinalysis requires urine sample to observe patient's urine processing based on proteins contained, its acidity, and so on. Some diagnostic processes require more that one lab tests

Some tests may extract same sample from patient's body. However, using separation technique like centrifuge in the lab, analysts will observe different parts of the sample. Hematology tests, for instance, separate blood cells from its plasma to count patient's blood cells amount. This is necessary to diagnose anemia, sickle cell, or other blood cell-related diseases. Clinical chemistry, on the other hand, uses chemical reaction to measure protein, pigments, or antibody in patient's blood. In other words, clinical chemistry does not observe patient's blood per se, but substances that it carries.

This classification is also important for structuring lab's cost. Each classification requires different reagents, controls, diluents, calibrators, automatic analyzer, even electrical cost.