Bloodstream pathogen-specific antibody positivity Positive bloodstream EBV monospot test 2024-07-05T10:44:08Z The monospot test is a latex agglutination test which utilizes equine erythrocytes as the primary substrate and tests for specific heterophile antibodies produced by the human immune system in response to EBV infection. When these specific antibodies are present in the patient's blood specimen, exposure to equine erythrocytes will lead to clumping of the sample, thus signaling a positive agglutination reaction.