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Monospot (Heterophile Assay)

Infectious Mononucleosis

Test Codes

EPIC: LAB5839, Beaker: MONO

Department

Special Chemistry

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)

Physician Office/Draw Specimen Preparation

Preparation for Courier Transport

Transport: Centrifuged collection tube or plasma specimen, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

• Hemolyzed specimens.
• Severely lipemic specimens.
• Specimens with gross bacterial contamination.

In-Lab Processing

Let serum specimens clot 30-60 minutes. Centrifuge to separate serum or plasma from cells. Transfer serum or plasma to a plastic transport tube.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months

Plasma Specimens (Aliquots)
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): 24 hours

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Transfusion Medicine Laboratory (Blood Bank)
Grosse Pointe Chemistry Laboratory
Lenox Main Laboratory
Livonia Main Laboratory
Royal Oak Special Chemistry Laboratory
Troy Hematology/Coagulation Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Main Laboratory

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 60 minutes.
Routine results available within 24 hours.

Reference Range

Reported as positive or negative.

Test Methodology

Latex Agglutination.

Interpretation

Assay results should be interpreted in regards to the patient's clinical symptoms.

Heterophile antibodies are usually detectable at the onset of symptoms and reach peak levels within 2 weeks. Heterophile antibody levels decline rapidly thereafter and are usually not detectable after 3 months. Heterophile tests are not suitable for testing sera from children under 12 years of age because they do not always produce heterophile antibodies during primary EBV infection. (1)

False-negative results may occur if the specimen is collected before detectable levels of heterophile antibodies have developed. A repeat assay is indicated for patients if their symptoms persist.

Clinical Utility

This assay is used as an aid in the diagnosis of infectious mononucleosis (IM).

Clinical Disease

Adolescents and adults who escape EBV infection during childhood experience infectious mononucleosis (IM) upon primary infection with EBV. IM is characterized by irregular fever, pharyngitis, and lymphadenopathy lasting 1 to 4 weeks. Hematological abnormalities include an absolute increase in lymphocytes and monocytes exceeding 50% and more than 15% atypical lymphocytes, lasting for at least 2 weeks. Liver function tests generally reveal a mild to moderate increase in SPGT, SGOT, bilirubin, and LDH levels. IM is usually a benign and self- limited disease. Complications including splenomegaly and splenic rupture, hepatitis, pericarditis, myocarditis, or central nervous system involvement (Guillain-Barre syndrome, Bell's palsy, transverse myelitis, and meningoencephalitis) may occur following IM infection. (1)

Epidemiology

Most cases occur sporadically. There is no seasonal variability.

Incubation Period

4 – 7 weeks.

Transmission

IM is transmitted via salivary contact through kissing or exposure to contaminated eating utensils.

Reference

1. Wiedbrauk D, Johnston SLG. Manual of Clinical Virology, Raven Press, New York, NY, 1993.

CPT Codes

86308

Contacts

Last Updated

3/18/2024