Common Test-Ordering Errors
Part 8: Overordered Microbiology Tests
Mumps, Measles and Varicella Serologies
Serology testing is problematic, particularly orders for both IgG and IgM, when one alone would answer the clinical questions. This is most notable for rubella, mumps, measles, and varicella. Through client investigations, we know that we receive many orders for both IgM and IgG serologies for these viruses when IgG alone would suffice. In most instances, the physician only wants to know if the patient has responded to an immunization. IgG is the test for this purpose, and ordering IgM, which is indicated for identifying acute infection, not only represents an additional, unnecessary expense, it can have major downstream consequences for the physician, patient, and the laboratory. These adverse consequences are especially true for rubella.
When IgG Answers Clinical Question
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