CPT Code 97033: Iontophoresis Billing Guide for Chiropractic Practices

What Is CPT Code 97033?

CPT code 97033 is the procedure code for iontophoresis, a physical medicine modality that uses direct electrical current to deliver medication (typically a corticosteroid or analgesic) through the skin to the underlying tissue. It is classified as a constant attendance modality under the CPT physical medicine section, meaning the provider or a qualified clinical staff member must be in direct contact with the patient throughout the treatment. Under the 2026 Medicare Physician Fee Schedule, 97033 reimburses approximately $15 to $18 per 15-minute unit in the non-facility setting, and it requires documentation of the medication delivered, the treatment site, the duration, and the clinical indication.

• What it treats: Iontophoresis is used in chiropractic settings primarily for localized inflammation, tendinitis, bursitis, and musculoskeletal pain where topical medication delivery is clinically indicated.
• Billing unit: 97033 is billed per 15-minute unit of direct patient contact. The provider must be present and in contact with the patient for the entire treatment duration to bill the code.
• Medicare limitation for chiropractors: Medicare does not cover 97033 when performed by a chiropractor. Medicare’s chiropractic benefit is limited to spinal manipulation (98940, 98941, 98942) only. Iontophoresis billed to Medicare under a chiropractor’s NPI will deny.

What Iontophoresis Covers

Iontophoresis is the transdermal delivery of ionized medication using a low-level direct electrical current. The provider applies electrode patches to the treatment area, one containing the medication and the other serving as the return electrode. The electrical current drives the medication through the skin and into the underlying tissue, targeting inflammation or pain at a specific site without systemic medication exposure.

In chiropractic practice, iontophoresis is most commonly used for localized musculoskeletal conditions: lateral epicondylitis (tennis elbow), plantar fasciitis, rotator cuff tendinitis, carpal tunnel syndrome, and localized joint inflammation. The medication is typically dexamethasone sodium phosphate (a corticosteroid) or lidocaine (an analgesic), and the treatment session runs 15 to 20 minutes.

CPT 97033 is classified as a constant attendance modality, which distinguishes it from supervised modalities like electrical stimulation (CPT 97014) or hot/cold packs (CPT 97010). Constant attendance means the provider must be in direct one-on-one contact with the patient for the entire duration of the treatment. The provider cannot treat another patient simultaneously while iontophoresis is running. This distinction affects staffing, scheduling, and revenue per hour. For how passive modalities like hot and cold packs (97010) compare to constant attendance modalities in billing, see our 97010 guide.

CPT 97033 vs. Other Physical Medicine Modalities

The key distinction between 97033 and the supervised modality codes (97014, 97010) is the attendance requirement. Iontophoresis requires the provider to be with the patient the entire time, which limits the number of patients the provider can see per hour. A chiropractic practice running iontophoresis on three patients simultaneously is billing incorrectly, because constant attendance means one provider, one patient, for the full treatment duration.

In our experience matching chiropractic providers with billing partners, the most common coding confusion involves 97033 and 97032 (manual electrical stimulation). Both are constant attendance modalities billed per 15 minutes, but they serve different clinical purposes. 97032 delivers electrical stimulation for pain relief or muscle re-education. 97033 delivers medication through the skin using electrical current. Using the wrong code results in a mismatch between the documentation and the claim, which triggers denials on audit.

How to Document CPT 97033 for Clean Claims

Documentation for 97033 must support four elements: the clinical indication, the medication delivered, the treatment parameters, and the constant attendance requirement.

1. Document the clinical indication. State the specific condition being treated and why iontophoresis is medically necessary. ‘Lateral epicondylitis with localized inflammation’ is supported. ‘Elbow pain’ without further detail is not.
2. Document the medication. Name the medication delivered (dexamethasone, lidocaine, acetic acid, or other), the concentration, and the volume. This is required because iontophoresis is a drug delivery modality, and the medication must be documented for the claim to make clinical sense.
3. Document the treatment parameters. Record the current intensity (milliamps), the duration of the treatment, the electrode placement sites, and the number of 15-minute units billed. A typical iontophoresis session runs 15 to 20 minutes at 1 to 4 milliamps.
4. Document constant attendance. The note must reflect that the provider was in direct contact with the patient for the entire treatment duration. If the note does not support constant attendance, the payer can downgrade the claim to a supervised modality rate or deny it entirely.
5. Link the diagnosis code to the treatment site. The ICD-10 code must match the anatomic site treated with iontophoresis. M77.10 (lateral epicondylitis) supports iontophoresis to the elbow. M79.3 (panniculitis, unspecified) does not. For how spinal manipulation codes pair with modality codes on the same visit, see our CPT 98940 billing guide.

Does Insurance Cover Iontophoresis for Chiropractors?

Coverage for CPT 97033 when performed by a chiropractor varies significantly by payer and by state. Here is the breakdown.

• Medicare: Not covered. Medicare’s chiropractic benefit covers only spinal manipulation (98940, 98941, 98942). All other services, including iontophoresis, are statutorily excluded when performed by a chiropractor. An ABN must be signed before the service if the patient is a Medicare beneficiary. For the full scope of Medicare chiropractic limitations, see our Chiropractic Medicare Coverage Modernization Act overview.
• Commercial payers: Coverage varies. Many commercial plans cover iontophoresis when performed by a chiropractor, but some require prior authorization, and some limit the number of units or sessions per diagnosis. Verify coverage with the patient’s specific plan before the first treatment.
• Workers’ compensation: Generally covered. Most state workers’ compensation programs cover iontophoresis when it is part of an approved treatment plan for a workplace injury. Documentation requirements may be stricter than commercial insurance.
• Personal injury / auto: Generally covered. PIP and MedPay policies typically cover iontophoresis as part of chiropractic care for auto accident injuries. Coverage limits vary by state and by policy.

One question we hear constantly from chiropractic practice managers is whether it is worth offering iontophoresis given the payer restrictions. The answer depends on the practice’s payer mix. A practice with a predominantly Medicare patient population will not recover the cost of the equipment. A practice with a commercial, workers’ comp, and PI payer mix can generate $60 to $75 per treatment session from iontophoresis, which adds meaningful revenue when combined with manipulation and other billable services on the same visit.

Common 97033 Billing Mistakes

Across the billing companies we vet for chiropractic practices, four 97033 errors appear most frequently.

• Billing 97033 to Medicare under a chiropractor’s NPI. This denies every time. Medicare does not cover iontophoresis when performed by a chiropractor. An ABN must be signed before the service so the patient can be billed directly.
• Missing the medication documentation. Iontophoresis is a drug delivery modality. A claim for 97033 without documentation of the medication name, concentration, and volume raises an immediate red flag on audit because the payer cannot determine what was delivered.
• Treating multiple patients simultaneously. 97033 is a constant attendance modality. The provider must be with the patient for the entire treatment. Billing 97033 for two patients whose treatment times overlap is a compliance violation.
• Confusing 97033 with 97032. 97032 is electrical stimulation (manual), which delivers current for pain relief or muscle re-education. 97033 is iontophoresis, which delivers medication through the skin using current. Different clinical purpose, different documentation, different code. Using the wrong one denies on audit.

Frequently Asked Questions

Next Steps

• For passive modality billing and how electrical stimulation compares, see our CPT 97010 guide.
• For spinal manipulation coding and how modalities pair with adjustments on the same visit, see our CPT 98940 billing guide.
• Ready to clean up your modality billing? Get matched with a chiropractic billing partner who knows the constant attendance codes.