From the Guidelines
No, this is not consistent with a false positive monospot, as the laboratory results indicate a recent or past Epstein-Barr virus (EBV) infection, with the elevated EBV Viral Capsid IgG and EBV Nuclear Antigen IgG antibodies suggesting an immune response to EBV. The patient's laboratory results show an elevated EBV Viral Capsid IgG (6.8) and EBV Nuclear Antigen IgG (2.9), which are indicative of an immune response to EBV 1. The absence of significant EBV Viral Capsid IgM (0.2) and Early Antigen IgG (<0.2) suggests that the infection is not in its earliest phase but has progressed somewhat.
The heterophile antibody test, which is what the monospot detects, is showing a value of 0.8, which is approaching the positive threshold of 0.9, as noted in the guidelines for utilization of the microbiology laboratory for diagnosis of infectious diseases 1. This pattern is consistent with infectious mononucleosis that is evolving from the acute to convalescent phase. Key points to consider include:
- The presence of VCA IgG and EBNA antibodies indicates infection with EBV, with the EBNA antibodies suggesting infection more than 6 weeks from the time of the sample 1
- The positive monospot combined with these EBV-specific antibody results confirms EBV infection rather than suggesting a false positive, as false-positive results may be found in patients with leukemia, pancreatic carcinoma, viral hepatitis, CMV infection, etc. 1
- The guidelines recommend EBV antibody testing for IgG and IgM to viral capsid antigen (VCA) and Epstein-Barr nuclear antigen (EBNA) to differentiate EBV infection from a mononucleosis-like illness caused by other pathogens 1.
From the Research
EBV Test Results
- The provided test results show:
- EBV Viral Capsid IgG: 6.8 (High)
- EBV Viral Capsid IgM: 0.2 (Low)
- EBV Nuclear Antigen IgG: 2.9 (High)
- EBV Early Ag IgG: <0.2 (Low)
- EBV Heterophile IgM: 0.8 (Low)
- These results indicate a past EBV infection, as evidenced by the high IgG levels and low IgM levels 2.
Monospot Test
- The Monospot test is a heterophile antibody test that detects antired cell antibodies produced during EBV infection 2.
- A positive Monospot test typically indicates a current or recent EBV infection.
- However, the test can also be positive in other viral infections, autoimmune diseases, and hematological malignancies 2.
False Positive Monospot
- The provided test results do not necessarily indicate a false positive Monospot test.
- The high IgG levels and low IgM levels suggest a past EBV infection, which could still result in a positive Monospot test 2.
- However, the low EBV Heterophile IgM level (0.8) may suggest that the Monospot test result could be a false positive, as this level is below the reference range.
- Further testing, such as virus-specific serology, may be necessary to confirm the diagnosis and rule out other possible causes of a positive Monospot test 2.
Note: The study 3 is not relevant to this question, as it discusses a case of lumbosacral intradural periradicular ossification and does not provide information on EBV or Monospot tests.