ICD-10 and CPT Codes for Lyme Disease Testing
For Lyme disease testing, use ICD-10 code Z11.8 (encounter for screening for other infectious and parasitic diseases) or Z20.8 (contact with and suspected exposure to other communicable diseases) for screening purposes, and CPT codes 86617 (Lyme disease antibody) for the initial EIA/IFA test and 86618 (Lyme disease confirmatory test, Western blot) for the reflex confirmatory test.
ICD-10 Diagnostic Codes
The appropriate ICD-10 code depends on the clinical scenario:
- Z11.8 - Encounter for screening for other infectious and parasitic diseases (when testing asymptomatic patients with potential exposure)
- Z20.8 - Contact with and suspected exposure to other communicable diseases (when patient has known tick exposure)
- R50.9 - Fever, unspecified (if presenting with fever and suspected Lyme disease)
- R21 - Rash and other nonspecific skin eruption (if erythema migrans is suspected but not confirmed)
- A69.20 - Lyme disease, unspecified (once diagnosis is confirmed)
- A69.21 - Meningitis due to Lyme disease (for confirmed Lyme neuroborreliosis)
- A69.22 - Other neurologic disorders in Lyme disease (for cranial neuropathies, radiculoneuropathy)
- A69.23 - Arthritis due to Lyme disease (for Lyme arthritis)
CPT Procedure Codes
The two-tiered testing approach recommended by IDSA/AAN/ACR requires specific CPT codes 1, 2, 3:
- 86617 - Antibody; Borrelia burgdorferi (Lyme disease) (initial screening test - EIA or IFA)
- 86618 - Antibody; Borrelia burgdorferi (Lyme disease) confirmatory test (Western blot)
The standard approach is to order CPT 86617 first, and if positive or equivocal, reflexively perform CPT 86618 2, 3, 4.
Important Coding Considerations
- Testing should only be ordered when clinically appropriate - The IDSA/AAN/ACR guidelines strongly recommend against routine testing in patients with psychiatric illness, dementia, Parkinson's disease, or typical ALS without epidemiologically plausible tick exposure 1, 2
- Two-tiered testing is mandatory for accurate diagnosis - Using only the initial screening test (86617) without confirmatory testing (86618) when positive/equivocal leads to false-positive results and inappropriate treatment 2, 3, 4
- Testing is appropriate for specific neurologic presentations including meningitis, painful radiculoneuritis, mononeuropathy multiplex, acute cranial neuropathies (especially VII and VIII), or spinal cord inflammation with appropriate exposure history 1, 2, 3
Common Pitfalls
- False-positive results occur in patients with infectious mononucleosis and autoimmune diseases, so clinical context is essential 2, 3
- Sensitivity is lower in early disease (the two-tiered approach has >98% specificity but reduced sensitivity in the first few weeks of infection) 2, 3
- Do not order testing for nonspecific symptoms without epidemiologic exposure or characteristic clinical findings 1, 2