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Common Test-Ordering Errors
Part 3: Misordered Tests

"Known" Mutations
Molecular vs. Nonmolecular Test for Given Disease
Chromosome Analysis


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Gene Test or Protein/Plasma Test?

Slide 11

June 2010

Let me use our apolipoprotein tests to explain. For example, apolipoprotein B is the major protein component of low-density lipoprotein (abbreviated LDL) and increased plasma concentration of Apo B-containing lipoproteins is associated with an increased risk of developing atherosclerotic disease. In fact, some studies have shown that circulating levels of apolipoprotein B may be a better indicator of risk that LDL levels.

In addition to plasma apolipoprotein B, we also offer a genetic test that assesses the patient’s DNA for the presence of abnormalities in the gene that encodes apolipoprotein B. The gene is called APOB and the name of the gene test is shown here. Note that the test name includes the phrase “molecular analysis” and describes the common 2 mutations for which we test (R3500Q and R3500W). Patients may have high lipids due to dietary causes, as well as a variety of inherited causes. One of the inherited causes is abnormalitiesin the APOB gene, which occurs in approximately 15% of autosomal dominant hypercholesterolemia cases. So, in this situation, we can test for the gene (using the molecular analysis test) or we can measure circulating lipoprotein levels (using the plasma test).

Again, it is important to critically read our test names to make sure the appropriate test is ordered. If there are similar test names, and the names alone do not make it clear which test to order, it often helps to review the supporting information, such as “Useful For”, in our test catalogs. When necessary, we contact the ordering physicians to clarify orders.  But, it is best to obtain that clarification before the specimen is collected.

Gene Test or Protein/Plasma Test?


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