Lyme Disease Antibody with Reflex to Immunoassay (IgG, IgM) (MTTT)

CPT Code: 86618
Order Code: 39733
Includes: If Lyme Disease Antibody is Positive or Equivocal (≥0.90), then Lyme Disease Supplemental Antibodies (IgG, IgM), Immunoassay will be performed at an additional charge (CPT code(s): 86617(x2)).
Alternative Name(s): Modified Two Tiered Test, Lyme Serology, Borrelia burgdorferi Antibodies, Lyme Disease, B burgdorferi, MTTT-2
ABN Requirement: No
Specimen: Serum
Volume:  1.0 mL
Minimum Volume:  0.5 mL
Container: Gel-barrier tube (SST)

Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions included with the provided shipping box.

Stability:

Ambient (15-25°C): 7 days
Refrigerated (2-8°C): 14 days
Frozen (-20°C): 30 days

Causes for Rejection: Gross hemolysis; Grossly lipemic; Grossly icteric

Methodology: Immunoassay (IA)

Turn Around Time:  3 to 5 days

Reference Range:

Clinical Significance: Lyme Disease Antibody with Reflex to Immunoassay (IgG, IgM) (MTTT) – This test is for the qualitative detection of antibodies against Borrelia burgdorferi, the causative agent of Lyme disease, using the modified two-tier testing (MTTT) algorithm. Initial testing is performed using a Lyme total (IgG and IgM) antibody assay and if positive or equivocal, the sample is then tested using separate IgG and IgM immunoassays. This algorithm differs from the STTT algorithm in that the second-tier assays are chemiluminescent immunoassays, not immunoblots. MTTT may be able to assist in the identification of Lyme disease with improved sensitivity earlier in infection compared to STTT.

Diagnostic testing for Lyme disease relies on a two-step algorithm to increase sensitivity and specificity. Testing is performed in patients presenting with signs and symptoms consistent with Lyme disease and with potential tick exposure in endemic regions. Most infections are transmitted by blacklegged ticks in the upper midwestern, northeastern, and mid-Atlantic states.

Negative results can occur in patient with recent infection (≤14 days). In persons with recent or past infection, both IgG and IgM can be detectable months to years after the infection has resolved. Therefore, it is recommended to interpret results in the context of the clinical picture, history, including exposure risk, and symptom onset.

References:

  1. Mead, P. et al. Updated CDC Recommendation for Serologic Diagnosis of Lyme Disease. Wkly Rep. 2019 Aug 16;68(32):703. doi: 10.15585/mmwr.mm6832a4.
  2. Suggested Reporting Language, Interpretation and Guidance For Lyme Disease Serologic Test Results. Association of Public Health Laboratories. April 2024.
  3. Sfeir MM, Meece JK, Theel ES, et al. Multicenter clinical evaluation of modified two-tiered testing algorithms for Lyme disease using zeus scientific commercial assays. J Clin Microbiol 2022; 60:e0252821.
  4. Tickborne Diseases of the United States. A Reference Manual for Healthcare Providers, Sixth Edition, 2022. Centers for Disease Control and Prevention.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.