Family Nurse Practitioner Exam

Which laboratory result is not typically associated with acute mononucleosis?

1. Lymphocytosis and/or atypical lymphocytes

2. Positive EBV titers for immunoglobulin (Ig) M and Ig G

3. Elevated liver function tests

4. Elevated creatinine and BUN

The correct answer is: Lymphocytosis and/or atypical lymphocytes

Acute mononucleosis is most commonly caused by the Epstein-Barr virus (EBV) and is characterized by a distinct profile of laboratory findings. Lymphocytosis and atypical lymphocytes are hallmark features of mono, with lymphocytosis typically noted in the complete blood count (CBC), while atypical lymphocytes are often observed in the peripheral smear. This abnormality is due to the immune response against the EBV. Positive EBV titers for immunoglobulin (Ig) M and Ig G are also classically associated with acute mononucleosis. The presence of IgM antibodies indicates a recent infection, while IgG antibodies reflect past exposure or later stages of the infection, confirming the diagnosis. Elevated liver function tests are frequently seen in cases of acute mononucleosis due to liver involvement, producing changes in aminotransferase levels (ALT and AST) as a result of viral hepatitis. In contrast, elevated creatinine and BUN are not typical findings associated with acute mononucleosis. While renal involvement can occur in certain viral infections, it is not a common laboratory result linked directly to mononucleosis. Therefore, this result does not fit the expected profile for acute mononucleosis and is the