ModifiedPremera BluecrossPolicy 15.01.026

ROUTINE TEST MANAGEMENT POLICY - 15.01.026 Testing for Vector-Borne Infections

Coverage and reimbursement guidance for laboratory testing used to diagnose a range of arthropod-borne infections (viruses, bacteria, and protozoa) including babesiosis, relapsing fevers, chikungunya, dengue, Zika, West Nile, malaria, ehrlichiosis/anaplasmosis, rickettsial diseases, Colorado tick fever, and related agents for Premera Bluecross members.

Policy Summary

PayerPremera Bluecross

PolicyTesting for Vector-Borne Infections

Policy CodePolicy 15.01.026

Change TypeNew policy + coding removals

Effective DateFeb. 6, 2026

Next Review Date

Key ActionOrder testing only when the clinical indications and specific diagnostic methods listed in the policy are met and document clinical suspicion and specimen timing to support reimbursement.

SourceLink

POLICY UPDATE CHANGES

New policy added for routine test management specifying reimbursable testing for a list of vector-borne and tickborne infections only when using specified diagnostic methods and clinical indications.

Removed CPT codes 86382, 86790, 87207, 87449, 87798, 87899.

Testing outside the outlined indications and screening of asymptomatic individuals are not reimbursable due to insufficient evidence of clinical benefit.

~22enumerated indication lines

CPT/HCPCS listedcoding entries present

Multipletests not reimbursable

2026-02-06

Coverage Criteria for Vector‑Borne and Tickborne Infection Testing

Pathogen-specific Indications

Covered when criteria below are met as described per pathogen-specific scenarios

Babesiosis: Reimbursable: Giemsa- or Wright-stain of blood smear or NAAT for individuals suspected of having babesiosis. Not reimbursable: IgG or IgM indirect immunofluorescence antibody (IFA) assay for Babesia.

See Note 1 for typical signs/symptoms.

Relapsing fever (Borrelia spp.): Reimbursable: For relapsing fever, testing varies by type: HTRF - serologic assays for Borrelia antibodies or PCR for Borrelia miyamotoi; LBRF - peripheral blood smear microscopy or PCR for Borrelia recurrentis; STRF/TBRF - dark-field microscopy, Wright/Giemsa smear, PCR for Borrelia spp., or serologic assays. Not reimbursable: culture testing for Borrelia.

See Notes 2-4.

Chikungunya: Reimbursable: Viral culture for diagnosis, NAAT on serum, or IFA IgM during acute and convalescent phases for suspected chikungunya.

See Note 5.

Colorado tick fever: Reimbursable: PCR testing or IFA for CTF-specific IgM antibodies.

See Note 6.

Dengue (DENV): Reimbursable: NAAT, IgM MAC-ELISA, NS1 ELISA, and confirmatory plaque reduction neutralization test for suspected DENV infection or symptomatic Zika individuals as specified. Not reimbursable: IgG ELISA or hemagglutination testing for DENV.

See Note 7.

Ehrlichiosis/Anaplasmosis: Reimbursable: NAAT of whole blood, IFA IgG, or microscopy for morulae detection. Not reimbursable: IFA IgM or standard blood culture.

See Note 8.

Malaria: Reimbursable: Rapid immunochromatographic diagnostic test or smear microscopy to diagnose, speciate, stage, and/or quantify parasitemia (can be repeated up to three times within three days if initial microscopy is negative). PCR to confirm Plasmodium species is reimbursable.repeat up to 3 times within 3 days if initial microscopy negative

See Note 9.

Rickettsial disease: Reimbursable: IFA IgG assay (two tests at least two weeks apart). Not reimbursable: standard blood culture, NAAT, or IFA IgM.two tests minimum two weeks apart

See Note 10.

West Nile virus (WNV): Reimbursable: IFA for WNV-specific IgG or IgM in serum or CSF and confirmatory plaque reduction neutralization test. For immunocompromised individuals, nucleic acid detection of WNV is reimbursable. Not reimbursable: NAAT for WNV in immunocompetent individuals.

See Notes 11-12.

Yellow fever virus (YFV): Reimbursable: NAAT for YFV and serologic assays for virus-specific IgM and IgG plus confirmatory plaque reduction neutralization test.

See chunk 6.

Zika virus: Reimbursable NAAT: symptomatic pregnant individuals up to 12 weeks after symptom onset with relevant travel/exposure history; symptomatic non-pregnant individuals with recent travel to areas with active CDC Zika Travel Health Notice when symptoms within last 7 days. Reimbursable NAAT/IgM and confirmatory PRNT for pregnant individuals up to 12 weeks post-symptom, fetuses with ultrasound findings, infants born to exposed/test-positive mothers, and infants with congenital signs. Not reimbursable: NAAT/IgM testing for symptomatic non-pregnant individuals without travel outside US/territories; asymptomatic screening in general exams for listed pathogens is not reimbursable.up to 12 weeks for certain pregnant individuals; within 7 days for symptomatic non-pregnant travelers

See chunks 6-7 and Notes 13-14.

Testing selection and confirmation criteria

Guidance on appropriate testing selection and confirmation

General testing principles: Select diagnostic modality based on pathogen, clinical timing, and specimen: NAAT/PCR for early or low‑level infections or immunocompromised patients; serology (IFA/ELISA/MAC‑ELISA) for many arboviruses and rickettsial diseases, requiring paired samples for confirmation; microscopy (blood smear) for malaria/babesia when available and expertise exists; culture reserved for research/epidemiology and specialized labs.

PCR sensitivity varies by organism and specimen; culture often not practical

When to use NAAT/PCR: Use NAAT/PCR for malaria in low parasitemia, to differentiate species, for immunocompromised patients or when prior flavivirus exposure complicates serology; use PCR for ehrlichiosis/anaplasmosis in the first week; consider PCR in suspected severe RMSF though whole blood PCR has low sensitivity except in severe disease.

PCR theoretical malaria LoD 0.02–1 parasite/µL

Serology for rickettsial and arboviral infections: Perform IFA/ELISA for IgG/IgM; obtain acute and convalescent sera 2–4 (or 2–10) weeks apart and require a minimum fourfold rise in titer to confirm acute infection; single or mistimed serology can be misleading due to past exposure or cross‑reactivity.

Rickettsial and tickborne testing

CDC/IDSA testing recommendations for rickettsial infections and related tickborne pathogens

Rickettsial serology: Perform IFA IgG on paired acute and convalescent serum samples collected 2-4 (or 2-10) weeks apart; require demonstration of at least a fourfold rise in titer for confirmation.fourfold rise

Single or inappropriately timed serologic tests can mislead

PCR and microscopy: PCR on whole blood may be useful early for ehrlichiosis and anaplasmosis; PCR has low sensitivity for R. rickettsii except in severe disease. Microscopy (morulae) on blood smear or buffy coat may indicate ehrlichiosis/anaplasmosis.

Negative PCR does not rule out rickettsial disease; do not withhold treatment for negative PCR

Culture/IHC: Culture and immunohistochemistry (IHC) are available for tissue or skin biopsy at specialized laboratories; routine blood cultures do not detect obligate intracellular Rickettsiae and are not recommended for routine confirmation.

Relapsing fever testing

Relapsing fever (soft and hard tick) testing

Microscopy/NAAT: In STRF, spirochetes can be detected by dark-field or stained peripheral blood smears early in symptomatic untreated patients; PCR on whole blood is more sensitive and preferred for diagnosis. Serology may be more sensitive when specimens are collected ≥14 days after symptom onset.

Serology most sensitive ≥14 days after onset; cross-reactivity with Lyme tests can occur

HTRF (B. miyamotoi): Diagnosis of hard-tick relapsing fever (Borrelia miyamotoi) is often made by PCR using whole blood; serologic EIA for GlpQ antigen is an available alternative with greater sensitivity when specimens are collected ≥14 days after onset.

Consider clinical and epidemiologic context due to cross-reactivity

Arbovirus and malaria testing

Arboviral and malaria testing

Malaria: Blood smear microscopy is the gold standard; perform immediately and report results as soon as possible (≤24 hours). RDTs are useful when microscopy is unavailable but must be confirmed by microscopy; PCR is useful to confirm species or mixed infections but is not usually timely for initial acute management.≤24 hours

Do not send out microscopy with long delays for acute diagnosis; repeat smears every 12–24 hours for up to three exams when indicated

Dengue: Acute (0–7 days): use NAAT (RT‑PCR) and/or NS1 antigen plus IgM (MAC‑ELISA) as appropriate; convalescent IgM ELISA recommended >7 days. PRNT may be required to distinguish flaviviruses in areas with co-circulation.0-7 days

PRNT to resolve cross-reactivity in endemic areas

WNV and other flaviviruses: IgM is the front-line screening assay; positive antibody screening requires confirmatory testing (PRNT) to differentiate flaviviruses. In immunocompromised patients where antibody development is delayed, virus detection by RT‑PCR or isolation may be useful.

Zika virus testing

Zika testing recommendations (pregnant, symptomatic, asymptomatic)

Asymptomatic pregnant: Routine Zika testing generally not recommended for those who lived in/traveled to US territories; NAAT may be considered up to 12 weeks after travel to area with active CDC Zika Travel Health Notice.up to 12 weeks

Guidance varies by exposure and travel history

Symptomatic pregnant: Collect specimens promptly up to 12 weeks after symptom onset: perform dengue and Zika NAAT and IgM on serum and Zika NAAT on urine; confirm IgM positives with PRNT against dengue/Zika and repeat NAAT on newly extracted RNA if NAAT positive but IgM negative to exclude false positives. Consider amniocentesis/placental/fetal testing in context.≤12 weeks

Repeat NAAT on newly extracted RNA if discordant results; use PRNT for confirmation

Symptomatic non-pregnant: If exposure in US/territories routine testing not recommended; if exposure in area with transmission, perform dengue and Zika NAAT on serum ≤7 days after symptom onset; perform IgM testing if NAAT-negative or >7 days; confirm positives with PRNT when needed.

Chikungunya testing

Chikungunya: Because chikungunya produces high viremia during the first week, diagnose acute infection by viral culture or NAAT on serum. Virus-specific IgM typically develops toward the end of the first week and may persist; consider serology in later presentations but note potential cross‑reactivity with related alphaviruses.first week

Consider broad differential and cross-reactivity with other alphaviruses

IDSA/ASM tickborne bacterial testing

IDSA/ASM recommended primary and alternative diagnostic procedures for tickborne bacteria

Relapsing fever borreliae: Primary: Wright/Giemsa/Diff-Quik stains of thin/thick blood smears. NAAT and serology are other options; optimum specimens include blood or bone marrow depending on species.

Specifics vary by Borrelia species

Lyme disease (Borrelia burgdorferi sensu lato): Early localized erythema migrans (EM): testing not routinely recommended. For later or disseminated disease use two‑tier testing (EIA followed by immunoblot or supplemental EIA) with paired acute and convalescent sera preferred; do not perform immunoblot unless initial EIA is positive or equivocal.acute and convalescent sera preferred

Follow two‑tier algorithm; immunoblot only after positive/equivocal EIA

B. miyamotoi: Primary test for acute infection: NAAT on blood; serology (EIA to GlpQ) available on serum as an alternative.

Optimum specimen: blood

Testing of asymptomatic individuals during routine general examinations is not reimbursable for the listed vector‑borne infections. Specifically, testing for babesiosis, chikungunya, Colorado tick fever, dengue (DENV), ehrlichiosis/anaplasmosis, malaria, rickettsial disease, tickborne relapsing fever (TBRF), West Nile virus (WNV), yellow fever virus (YFV), and Zika virus performed in asymptomatic persons without abnormal findings will be denied as not reimbursable. This exclusion reflects the policy requirement that testing be limited to the specific clinical indications and diagnostic methods described in the policy to support medical necessity.

Indirect immunofluorescence antibody (IFA) testing for rickettsial infections has limited sensitivity early in illness. IFA assays are typically unreliable during the first 5 days of infection because antibody levels are often too low to detect; therefore early serology alone can yield false‑negative or misleading results. Clinicians should rely on appropriate timing (paired acute and convalescent sera) or alternative modalities (PCR or tissue testing when indicated) rather than a single early IFA IgM or IgG result.

Culture for tickborne rickettsial organisms is generally not a routine confirmatory diagnostic method. Because many rickettsiae are obligate intracellular organisms, culture requires specialized cell culture techniques and high‑biosafety facilities; it is therefore reserved primarily for specialized laboratories, research, or public health/epidemiologic purposes rather than routine clinical diagnosis.

Routine hospital blood culture systems are not suitable for detection of Rickettsia species. Rickettsiae cannot be isolated with standard blood culture techniques; culture isolation and immunohistochemical (IHC) assays are available only at specialized laboratories and are not part of routine in‑hospital blood culture workflows.

Arboviral testing (for Zika, dengue, and related flaviviruses) should be performed only in appropriately equipped laboratories by trained staff and interpreted with attention to specimen type and timing. Molecular assays (NAAT/RT‑PCR) are preferred for early detection but have limited windows of RNA detectability; serologic testing requires careful interpretation because of cross‑reactivity and prior flavivirus exposure. For Zika, WHO and other guidance emphasize use of whole blood/serum/plasma and urine for NAAT and recommend confirmatory testing (eg, PRNT) when necessary.

Tests and methods not specified in the policy, testing performed outside the defined clinical indications, and screening of asymptomatic individuals are not reimbursable. Examples include IFA for Babesia, NAAT for WNV in immunocompetent persons outside specified indications, and other laboratory methods performed without meeting the policy’s method‑and‑indication requirements; such claims risk denial due to insufficient evidence of clinical benefit.

Several specific tests are explicitly identified as not reimbursable under this policy. Notable examples include Babesia IFA IgG/IgM, culture testing for Borrelia species causing relapsing fever, IFA IgM for ehrlichiosis/anaplasmosis, and NAAT for WNV in immunocompetent individuals. Providers should reference the policy’s indications list to determine which methods are covered for each pathogen.

Rapid antigen or point‑of‑care tests (for example, the BinaxNOW malaria assay) provide rapid results but have limitations outside endemic settings. Published evaluations report lower sensitivity and potential misclassification (eg, reported sensitivity ~84.2% in some non‑endemic evaluations), and rare false‑positives from cross‑reacting organisms have been described. When used in non‑endemic areas, rapid tests should not be relied on as the sole confirmatory method and positive or clinically discordant results should be confirmed with microscopy, NAAT, or other appropriate testing.

Two‑tier testing for Lyme disease (EIA followed by immunoblot or supplemental EIA) should not be performed unless an initial EIA is reported as positive or equivocal. Performing supplemental immunoblots or additional confirmatory assays without an appropriate screening EIA can lead to inappropriate testing and is not consistent with IDSA/ASM guidance.

Screening asymptomatic individuals for vector‑borne infections in the absence of clinical signs, symptoms, or specified exposure criteria is considered not medically necessary and is not reimbursable. Testing should be reserved for patients who meet the clinical and situational indications described in the policy (eg, symptomatic individuals with relevant travel/exposure history, pregnant patients meeting Zika criteria, infants with congenital concerns).

Coding and Code Definitions

Covered/Listed CPT CodesCPT

86280	Hemagglutination inhibition test (HAI).
86619	Antibody; Borrelia (relapsing fever).
86666	Antibody; Ehrlichia.
86753	Antibody; protozoa, not elsewhere specified.
86757	Antibody; Rickettsia.
86788	Antibody; West Nile virus, IgM.
86789	Antibody; West Nile virus.
86794	Antibody; Zika virus, IgM.
87040	Culture, bacterial; blood, aerobic, with isolation and presumptive identification of isolates (includes anaerobic culture, if appropriate).
87468	Infectious agent detection by nucleic acid (DNA or RNA); Anaplasma phagocytophilum, amplified probe technique.

1–10 of 14

1/2

Proprietary/Other CodesHCPCS

0043U	Tick - borne relapsing fever Borrelia group, antibody detection to 4 recombinant protein groups, by immunoblot, IgM Proprietary test: Tick - Borne Relapsing Fever Borrelia (TBRF) ImmunoBlots IgM Test Lab/Manufacturer: IGeneX Inc.
0044U	Tick - borne relapsing fever Borrelia group, antibody detection to 4 recombinant protein groups, by immunoblot, IgG Proprietary test: Tick - Borne Relapsing Fever Borrelia (TBRF) ImmunoBlots IgG Test Lab/Manufacturer: IGeneX Inc.

Removed CPT CodesCPT

86382	removed
86790	removed
87207	removed
87449	removed
87798	removed
87899	removed

inv-23: PCR limit of detection (theoretical)

PCR limit of detection (theoretical)0.02 to 1 parasite/microL

ContextEstimate derived from PCR analytic sensitivity for Plasmodium species used as a reference standard in diagnostic studies

ImplicationNAAT/PCR can detect low-level parasitemia when microscopy or RDT may be insensitive

inv-24: Serologic confirmation threshold

Confirmation thresholdFourfold rise in antibody titer between acute and convalescent samples

Specimen timing

Provider Actions, Documentation, and Billing Considerations

Note

Testing modality considerations

Select testing modality based on clinical context and timing: use microscopy (Giemsa/Wright) and NAAT/PCR for acute infections where rapid detection is critical (e.g., babesiosis, Borrelia miyamotoi, ehrlichiosis/anaplasmosis, malaria); reserve serology (IFA/ELISA/PRNT) primarily for convalescent confirmation (paired specimens) or when NAAT is negative or unavailable. Note that IFA IgG is generally more specific than IgM; IgM testing may cross-react and produce false positives for spotted fever group rickettsiae and other agents.

Choose NAAT/PCR for acute-phase diagnosis when available and appropriate.
Use blood smear microscopy (thick and thin) for malaria and babesiosis; repeat microscopy every 12–24 hours up to three exams before ruling out malaria if initial microscopy is negative.
Avoid relying solely on IgM results for rickettsial diseases due to cross-reactivity risk.

Note

Prior authorization not specified

This policy does not specify that prior authorization is required for the listed tests. Order testing that meets the clinical indications and documentation requirements in this policy; verify member benefits for any plan-specific prior authorization rules.

Background and Epidemiology

Arthropod vectors (mosquitoes, ticks, fleas, mites) transmit a diverse array of bacterial, protozoan, and viral pathogens that cause diseases such as Zika, West Nile, chikungunya, dengue, malaria, babesiosis, rickettsial diseases, ehrlichiosis/anaplasmosis, and relapsing fevers. Diagnostic approaches vary by pathogen and clinical context and include smear microscopy, NAAT/PCR, serologic assays (eg, IFA, ELISA), culture in specialized settings, and confirmatory neutralization testing (PRNT) for flaviviruses.

Definitions and Abbreviations

inv-52: Arboviruses

DefinitionArthropod-borne viruses including Zika virus, West Nile virus (WNV), chikungunya, dengue (DENV), yellow fever (YFV), and Colorado tick fever (CTF)

ScopeArboviruses transmitted by mosquitoes or ticks causing systemic and neurologic disease presentations

Related pathogensIncluded among arthropod-borne agents alongside protozoa (Plasmodium, Babesia) and bacteria (Rickettsia, Ehrlichia, Anaplasma, Borrelia)

inv-53: Abbreviations/Terminology

Common abbreviationsIFA, IgG, IgM, PCR, NAAT, PRNT, WNV, YFV, DENV, RMSF, CSF

Other termsRT-PCR, qPCR, RDT, HAI, MAC-ELISA, EIA

Policy Revisions and Effective Dates

2026-02-06Effective date / coding updateLatest

Policy became effective for dates of service on or after 2026-02-06 following provider notification; coding update removed CPT codes 86382, 86790, 87207, 87449, 87798, and 87899.

2025-11-01Policy addition / approval

New policy approved October 14, 2025 and recorded on 11/01/25 adding coverage criteria that testing for listed vector-borne infections is reimbursable only when performed using specified diagnostic methods and clinical indications.

Note

Policy Summary

PayerPremera Bluecross

PolicyTesting for Vector-Borne Infections

Policy CodePolicy 15.01.026

Change TypeNew policy + coding removals

Effective DateFeb. 6, 2026

Next Review Date

Key ActionOrder testing only when the clinical indications and specific diagnostic methods listed in the policy are met and document clinical suspicion and specimen timing to support reimbursement.

SourceLink

On This Page

IFA insensitive in first week for most tickborne rickettsial diseases

Rapid diagnostic tests and limitations: RDTs (eg, BinaxNOW for malaria) offer speed but can have lower sensitivity and misclassification in non‑endemic areas and potential for false positives (eg, Salmonella typhi reported to cause false-positive malaria on BinaxNOW); interpret RDT results in clinical context and confirm with microscopy or PCR when indicated.

BinaxNOW sensitivity ~84.2% reported

Culture not routinely used due to availability and biosafety requirements

Viremia often absent by time of neuroinvasive presentation

Use PRNT to resolve cross-reactivity when definitive diagnosis required

Infants with possible congenital Zika: Collect specimens as soon as possible after birth: infant serum NAAT and IgM, urine NAAT, and CSF testing if obtained; perform PRNT for confirmatory testing when indicated and repeat testing at 18 months if initial sample non‑negative.

Interpret amniotic fluid and placental testing within their limitations

Anaplasma/Ehrlichia: Primary acute test: NAAT on whole blood. Alternate: Wright/Giemsa stain of blood or buffy coat if experienced technologists available during the first week; serology (acute and convalescent IFA IgG) is not recommended for acute diagnosis.first week

Ehrlichia ewingii may be diagnosed definitively by microscopy in first week

Collect acute sample early in illness and convalescent sample 2–4 (or 2–10) weeks later to demonstrate rise

RationaleSingle elevated titers are insufficient; serial titers required to confirm acute rickettsial infection

inv-25: Serologic confirmation threshold duplicate

Minimum demonstrationDemonstration of at least a fourfold rise in antibody titer

Testing requirementPerform paired IFA/serologic testing on acute and convalescent sera to show seroconversion

Clinical noteInappropriately timed or single serologic tests can lead to misinterpretation of results

inv-26: Microscopy turnaround

Turnaround expectationResults available as soon as possible, ≤24 hours

Operational guidanceDo not batch microscopy or send out with delays that make results available only days to weeks later

Confirmation noteWhen RDTs are used, microscopy confirmation should occur as soon as possible because species and parasitemia data are critical

No prior authorization requirement is stated in this policy text.
Providers should still confirm member-specific benefit/authorization rules separately.

Denial Risk

Triggers for denial

Claims may be denied when tests are ordered outside the specified clinical indications, when non‑recommended testing modalities are used (e.g., single untimed serologic tests, IgM-only serology for certain rickettsial diseases), or when required specimen timing and documentation are not provided.

Testing of asymptomatic individuals during routine exams is not reimbursable.
Single or inappropriately timed serologic tests (without paired acute/convalescent comparison) risk denial.
Use of non‑reimbursable methods listed in the policy (e.g., certain IgM IFAs, culture for some agents) may be denied.

Note

IgM testing limitations can risk incorrect conclusions

IgM assays can produce false‑positive results because of cross‑reactivity (for example, in spotted fever group rickettsiae). Do not base definitive diagnosis or public‑health reporting solely on IgM results for rickettsial diseases; confirm with paired IgG serology or alternative methods (PCR, tissue testing) as indicated.

Interpret IgM cautiously—particularly for RMSF and other SFG rickettsiae.
Confirm suspected infections with IgG serologic conversion (fourfold rise) or with PCR/tissue testing when possible.

Note

Timeliness requirement for malaria microscopy

For suspected malaria, microscopy must be performed promptly and results should be available ≤24 hours of presentation; STAT Giemsa-stained thick and thin films are preferred and should be repeated every 12–24 hours for a total of up to three examinations before ruling out malaria.

Perform microscopy STAT; do not batch or delay testing.
Repeat thick and thin smear microscopy every 12–24 hours up to three times if initial smear is negative and clinical suspicion persists.
Confirm any rapid diagnostic test (RDT) results with microscopy as soon as possible.

Documentation Required

Laboratory quality requirement

Use only laboratory tests and platforms that have undergone independent, comprehensive assessment of quality, safety, and performance and are performed in appropriately equipped laboratories by trained personnel. Laboratory‑developed tests (LDTs) must be validated and performed in CLIA‑regulated high‑complexity laboratories.

Prefer tests with independent performance assessment (FDA-cleared/approved or externally validated).
LDTs are regulated under CLIA as high‑complexity tests and must be validated by the performing laboratory.
Ensure testing is performed in labs with appropriate biosafety, equipment, and trained staff.

Documentation Required

Clinical indication documentation

Document the clinical indication and supporting findings when ordering tests: signs/symptoms, exposure/travel history, timing of symptom onset, and severity. Only order tests when the individual meets the policy’s clinical suspicion or situational criteria.

Record relevant exposure/travel history and symptom onset date.
Document why the specific test modality was selected (e.g., PCR for acute suspicion, serology for convalescent confirmation).

Note

Recommended diagnostic specimens and evidence

Order appropriate diagnostic specimens per pathogen and method: Giemsa- or Wright‑stained peripheral blood smears and NAAT/PCR on whole blood for babesiosis; peripheral blood smears or PCR for relapsing fever Borrelia species; NAAT/PCR for Anaplasma/Ehrlichia; NAAT (and NS1 or MAC‑ELISA) for dengue; NAAT and serology for Zika; IFA/ELISA/PRNT for arboviral serology when indicated.

Babesiosis: blood smear (thin/thick) and PCR; serology not recommended for acute diagnosis.
Relapsing fever: blood smear (during febrile episode), PCR, or serology (paired) as appropriate.
Arboviruses (DENV, Zika, WNV): use NAAT/NS1 early and serology/PRNT for confirmation per epidemiologic context.

Documentation Required

Specimen timing and clinical correlation

Collect specimens at clinically appropriate intervals and correlate results with illness timeline: obtain an acute sample early in illness for NAAT/microscopy and collect convalescent serum 2–4 (CDC: 2–10) weeks later for serologic comparison. Demonstration of a fourfold rise in IgG titer between acute and convalescent samples is confirmatory for many tickborne rickettsial diseases.

Acute specimen: collect during first week for PCR or microscopy when possible.
Convalescent specimen: collect 2–4 weeks later (CDC notes 2–10 weeks for some rickettsial infections).
Document collection dates and link results to clinical course to demonstrate seroconversion when needed.

Documentation Required

Serologic specimen pairing and documentation

For serologic confirmation, obtain paired acute and convalescent specimens with collection dates recorded (typically 2–4 weeks apart; CDC notes 2–10 weeks for rickettsial disease). A ≥4‑fold rise in IgG titer is required to confirm acute infection for many tickborne agents; elevated single titers alone are insufficient.

Always document both specimen collection dates in the chart and on the requisition.
Failure to obtain paired specimens and show seroconversion may result in non‑reimbursable claims.

Documentation Required

Specimen collection documentation

Collect optimum specimens per guidance (e.g., paired serum and CSF within 24 hours for neuroborreliosis when indicated; blood for NAAT and microscopy for babesiosis and malaria; biopsy/tissue for PCR or immunohistochemistry in some rickettsial diagnoses). Ensure specimens are handled and transported per lab instructions to preserve sample integrity.

For neuroborreliosis: paired serum and CSF collected within 24 hours when performing antibody index testing.
Transport motile/fragile specimens promptly (darkfield) to preserve viability for microscopy/PCR.

Documentation Required

Required documentation

Required documentation in the medical record: clinical signs/symptoms, exposure/travel history, date of symptom onset, rationale for chosen test modality, specimen collection dates, and laboratory method used. Link laboratory reports to the clinical note demonstrating that policy clinical indications were met.

Specify the test method performed (e.g., NAAT/PCR, IFA IgG/IgM, microscopy) in the record.
Include specimen collection date/time and clinical justification to support medical necessity for reimbursement.

Note

Empiric treatment and diagnostic approach

Empiric antimicrobial therapy should not be delayed when clinical suspicion for severe infections such as RMSF is high; obtain appropriate diagnostic specimens before antibiotics when feasible, but treat empirically if delaying therapy would increase risk. Diagnostic confirmation often relies on paired serology (convalescent rise) or PCR/biopsy when available.

Do not delay empiric therapy for suspected RMSF while awaiting confirmatory results if clinically indicated.
Obtain acute diagnostic specimens before antimicrobial initiation when possible to maximize test sensitivity.

Step Therapy

No step therapy specified

No step therapy or sequencing of tests is specified in this policy; selection of tests should follow clinical guidelines and the diagnostic pathway appropriate to the suspected pathogen and timing of illness.

Clinicians should choose the most appropriate test for the clinical scenario (e.g., NAAT for acute infection, serology for convalescent confirmation).

Note

Sequential testing for malaria

For malaria, perform sequential testing per guideline recommendations: STAT Giemsa‑stained thick and thin blood films, repeating every 12–24 hours for up to three exams before ruling out malaria in suspected cases; follow with PCR for species confirmation when indicated.

Repeat microscopy every 12–24 hours for up to three exams if clinical suspicion persists after a negative initial smear.
Use PCR to confirm Plasmodium species when available and when species identification will affect management.

StandardsTerminology table lists organizational acronyms (CDC, IDSA, ASM, WHO) used in guidance

inv-54: NAAT

DefinitionNucleic acid amplification testing (NAAT) such as PCR or RT‑PCR for detecting pathogen DNA/RNA

PerformanceOften more sensitive and specific, especially for low-level parasitemia or early infection

Use casesRecommended for early diagnosis, species differentiation, immunocompromised patients, or when serology is confounded by prior flavivirus exposure

inv-55: IFA

DefinitionIndirect immunofluorescence antibody assay (IFA) — reference serologic test for many tickborne rickettsial diseases

Testing protocolRequires paired acute and convalescent sera collected 2–4 (or 2–10) weeks apart to detect fourfold rise

LimitationsInsensitive in the first week of illness; single elevated titers are not diagnostic of acute infection

inv-56: indirect immunofluorescence antibody assay

SynonymIndirect immunofluorescence antibody assay (IFA)

RoleReference standard serologic test for tickborne rickettsial infections when paired sera are obtained

TimingCollect acute and convalescent samples 2–4 (or 2–10) weeks apart

inv-57: polymerase chain reaction

LabelPolymerase chain reaction (PCR)

UtilityUseful for early detection of ehrlichiosis/anaplasmosis, malaria species identification, Babesia and Borrelia diagnostics; sensitivity varies by organism and specimen

LimitationPCR for Rickettsia rickettsii has low sensitivity except in severe disease; timing and specimen type affect yield

inv-58: PRNT

DefinitionPlaque reduction neutralization test (PRNT) — reference standard for detection and confirmation of arboviral antibodies, improving specificity among flaviviruses

AvailabilityPRNTs are typically available only at select public health or reference laboratories (eg, CDC)

Use caseRecommended to distinguish cross-reactive flavivirus IgM/IgG results (eg, dengue vs Zika) and to confirm serologic positives

inv-59: LDT

DefinitionLaboratory-developed test (LDT) — an in-house assay developed and validated by a laboratory for clinical use

Regulatory statusLDTs are regulated under CLIA as high-complexity tests and must be validated by the performing laboratory prior to clinical use

FDA noteLDTs are not FDA-cleared/approved for clinical use but remain subject to CLIA validation requirements

inv-60: Reimbursable testing definition

DefinitionReimbursable testing — testing for the listed vector-borne infections only when performed using the specific diagnostic methods and clinical indications outlined in this policy

Covered agentsIncludes babesiosis, relapsing fever, chikungunya, Colorado tick fever, dengue, ehrlichiosis/anaplasmosis, malaria, rickettsial disease, West Nile, yellow fever, and Zika

ExclusionsAll other testing methods, testing outside these indications, and screening of asymptomatic individuals are not reimbursable

New policy: reimbursable testing limited to specified methods/indications

This policy is a new routine test management entry that restricts reimbursable testing to listed infections only when performed using the specific diagnostic methods and clinical indications outlined; providers should follow these requirements to support coverage.

Effective for dates of service on or after Feb. 6, 2026, following provider notification.
Testing outside the outlined methods/indications and asymptomatic screening are not reimbursable.