HCPCS code S0030: Injection, metronidazole, 500 mg

Key Takeaways

HCPCS code S0030 describes injection of metronidazole, 500 mg, and is classified as a deleted HCPCS Level II S-code

S codes are not recognized by Medicare Part B; S0030 was used by Medicaid and private payers only, and coverage varies by state

Crosswalk to J0694 (Injection, metronidazole, 500 mg) for current J-code billing, or J3490 for unclassified drug claims when payer requires it

Pabau’s claims management software helps IV therapy and infusion clinics track drug billing codes, NDC numbers, and payer-specific requirements in one place

HCPCS code S0030 carries the official descriptor “Injection, metronidazole, 500 mg.” It belongs to HCPCS Level II, the section administered by the Centers for Medicare and Medicaid Services (CMS) for supplies, drugs, and services not captured by CPT codes. Within Level II, S0030 falls under the S-code section: temporary national codes established for use by state Medicaid programs and private payers.

Multiple authoritative HCPCS databases list S0030 as a deleted (terminated) code. A deleted code means CMS has officially retired it from the active HCPCS Level II file. Providers who attempt to submit this code to payers without verifying its current status risk automatic rejection. Before billing any S-code on an active claim, confirm its standing in the current CMS annual HCPCS update file or contact your Medicare Administrative Contractor (MAC) for guidance.

What S0030 describes: metronidazole injection 500 mg

Metronidazole is an antibiotic and antiprotozoal agent used intravenously when oral administration is not appropriate. The intravenous formulation at 500 mg per dose that S0030 was designed to capture is commonly used in hospital outpatient settings, infusion clinics, and skilled nursing facilities.

Clinicians administering IV metronidazole typically indicate one of several established clinical scenarios where the drug is appropriate, including anaerobic bacterial infections, IV therapy clinic management protocols, and certain protozoal infections.

Per FDA labeling, approved indications for metronidazole IV include anaerobic bacterial infections (intra-abdominal, skin and skin structure, gynecologic, bone and joint, CNS, endocarditis, septicemia), surgical prophylaxis for colorectal procedures, and treatment of trichomoniasis, giardiasis, and amebiasis when parenteral administration is clinically indicated. Coders should not extend clinical indications beyond FDA labeling when supporting medical necessity documentation.

• Anaerobic bacterial infections: intra-abdominal, gynecologic, CNS, bone and joint
• Surgical prophylaxis: colorectal procedures requiring perioperative antibiotic coverage
• Protozoal infections: trichomoniasis, giardiasis, amebiasis when oral route is contraindicated
• Route: intravenous infusion only (the descriptor specifies injection/infusion, not oral)
• Unit: one unit equals one 500 mg dose administered

Understanding HCPCS S codes and temporary national codes

S codes sit within HCPCS Level II but occupy a distinct policy space from J-codes and CPT codes. CMS established the S-code section as temporary national codes primarily for use by state Medicaid programs and Blue Cross Blue Shield plans. That classification has two practical consequences for billing staff: first, Medicare Part B does not recognize or reimburse S codes under any standard coverage policy; second, Medicaid coverage varies by state and private payer acceptance varies by contract.

J-codes, by contrast, are HCPCS Level II codes CMS maintains specifically for Medicare-covered injectable drugs and chemotherapy agents. When a drug has both an S-code and a J-code equivalent, Medicare-participating providers must use the J-code. Understanding this distinction prevents the single most common billing error for codes like S0030: submitting an S-code on a Medicare claim and receiving an automatic rejection. For a broader view of how these systems interact, the AAPC HCPCS code lookup provides context on Level II code sections and their payer applicability.

Is S0030 covered by Medicare or Medicaid?

Medicare Part B does not reimburse HCPCS code S0030 or any other S-code. This is a structural policy, not a code-specific coverage determination. S codes as a category are excluded from Medicare Part B fee schedule reimbursement under CMS rules. Submitting S0030 on a Medicare claim will result in automatic denial regardless of the clinical indication or documentation provided. Running an insurance eligibility verification before treatment helps billing teams identify the patient’s payer type and select the correct code set before a claim is ever submitted.

Medicaid coverage is a different question. State Medicaid programs can, and often do, recognize S codes. Coverage for S0030 (when it was active) varied by state: some state programs included it in their drug reimbursement schedules, others did not. Because the code is now deleted, any Medicaid program that previously covered S0030 will have updated its formulary to reflect the deletion. Providers submitting to state Medicaid should use the current replacement code (see crosswalk section below) and confirm acceptance with the state’s Medicaid billing authority.

Private payers follow their own coverage determinations. If a commercial plan’s fee schedule still references S0030 by contract, providers should request a contract update and submit using the current replacement code with a notation referencing the deletion. The CMS Physician Fee Schedule lookup tool confirms which HCPCS codes carry active Medicare reimbursement rates.

Is S0030 a deleted HCPCS code? Status and history

S0030 is classified as a deleted HCPCS code across authoritative reference sources including AAPC, HCPCSdata.com, and FindACode. A deleted code has been officially removed from the active HCPCS Level II annual code file by CMS. The deletion means no payer should accept the code as a valid billing identifier after its termination date, regardless of prior coverage history.

When a provider encounters S0030 on an older payer contract, an explanation of benefits (EOB), or an electronic remittance advice, the appropriate response depends on context. On a historical claim being reviewed for appeal, the code was valid for the service date in question and may still be referenced. On a new claim being prepared today, S0030 should not be used. Providers should flag the code during charge capture review and substitute the appropriate current crosswalk alternative before submission.

CMS issues quarterly HCPCS updates and an annual update effective each January 1. Billing teams working with drug injection codes should subscribe to their MAC’s provider bulletin service to receive notifications when codes are added, revised, or deleted. The CMS HCPCS Level II overview page provides links to the current annual code file and quarterly update files.

S0030 crosswalk: Replacement and related codes

Two HCPCS codes are most relevant as crosswalk alternatives when S0030 would historically have been used. Understanding which applies requires matching the payer type and confirming current code status with the relevant authority before claim submission.

J0694 (Injection, metronidazole, 500 mg) appears in the CMS HCPCS Level II file as the J-code equivalent for the same drug and dose. Because J-codes are recognized by Medicare Part B and generally accepted by Medicaid programs and commercial payers, J0694 is the appropriate primary crosswalk when billing metronidazole 500 mg IV. Providers should verify J0694’s current active status against the most recent CMS HCPCS annual update file before use.

J3490 (Injection, drug, unclassified) is a confirmed active HCPCS code maintained by CMS for injectable drugs that lack a specific code. It is a well-established safety net code. When using J3490, payers typically require the drug name, NDC, dose, and a copy of the invoice or drug acquisition cost documentation. Using J3490 for a drug that has its own specific J-code (such as J0694) is generally not appropriate and may result in denial.

J3490 is most relevant when a payer specifically instructs providers to use an unclassified code, or when J0694’s status cannot be confirmed for a given claim date. For revenue cycle management teams, having clear crosswalk documentation in the billing system reduces the risk of using the wrong code for the service date.

Billing guidelines for metronidazole IV infusion

Whether billing under J0694, J3490, or responding to a legacy S0030 reference, the documentation requirements for metronidazole IV infusion follow the same core standards. Submitting a clean claim for an injectable drug requires specific fields that differ from standard office visit claims. Missing any of them is a leading cause of drug claim denials.

Documentation requirements

• Physician or provider order: signed order specifying drug name (metronidazole), dose (500 mg), route (IV/intravenous), frequency, and duration
• NDC number: National Drug Code for the specific product administered; required on Medicaid drug claims and by many commercial payers
• Dose administered: quantity of units billed must match dose administered; one unit of S0030 or J0694 equals one 500 mg dose
• Diagnosis codes: ICD-10-CM codes supporting the clinical indication (e.g. anaerobic infection, specific protozoal infection) to establish medical necessity
• Place of service: outpatient hospital (22), office (11), or infusion center (19) as applicable; affects reimbursement methodology
• Date and time of infusion: documented in the clinical record; required for infusion claims that may also bill infusion administration CPT codes

For Medicaid claims in particular, NDC reporting is a federally required condition of reimbursement for drug claims. CMS confirmed this requirement universally across state Medicaid programs. The NDC must appear in the correct claim field with the correct unit qualifier (UN for each 500 mg vial or dose). Using the superbill as a structured documentation tool during the encounter makes it easier for billing staff to capture NDC and dose information at point of care before claim preparation begins.

How to avoid common billing errors with S0030

Billing staff encounter four consistent error patterns with deleted codes like S0030. Each has a practical fix that reduces managing claim denials after the fact.

• Submitting a deleted code: S0030 is not active. Using it on a current claim will generate an invalid code rejection. Set up a billing system edit that flags S0030 and prompts substitution with J0694 before claim transmission.
• Incorrect unit reporting: S0030 and its crosswalk J0694 are billed per 500 mg dose. If 1,000 mg (two vials) were administered, bill two units. Billing one unit for a multi-dose infusion undercaptures reimbursement; billing incorrectly overbills and creates audit risk.
• Missing NDC on Medicaid claims: Medicaid requires the NDC number, unit qualifier, and quantity on all drug claims. Submitting without a complete NDC will result in denial. Build NDC capture into the infusion record at time of administration, not retrospectively.
• Failing to verify payer S-code coverage: Even when a code is active, S codes require pre-billing verification with each payer. Not all commercial plans accept S-code submissions. Verify coverage status before submitting any S-code claim, and contact the payer to confirm its coding requirements when the contractual language is ambiguous.
• Using J3490 when J0694 applies: J3490 is appropriate only when no specific code exists for the drug being billed. Using an unclassified code unnecessarily triggers additional documentation requirements and review scrutiny. Use J0694 as the primary code for metronidazole 500 mg IV.

Systematic medical billing compliance reviews that include drug injection code audits help practices catch these patterns before they accumulate into a pattern of improper billing that attracts payer audits. Reviewing remittance adjustment reason codes on denied drug claims reveals which of the above errors is occurring most frequently in a given billing cycle.

When reviewing denial codes in medical billing, a recurring CO-4 (incorrect code) on drug injection claims is a reliable indicator that a crosswalk or code status issue exists in the charge capture process.

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Reimbursement considerations for metronidazole IV

Because S0030 is a deleted code with no active fee schedule entry, no specific reimbursement rate applies to it under any current payer schedule. Reimbursement for metronidazole 500 mg IV now follows the crosswalk code. For Medicare claims using J0694, the applicable reimbursement is the average sales price (ASP)-based rate published in the Medicare Part B Physician Fee Schedule or Part B drug pricing file, updated quarterly by CMS.

Medicaid reimbursement for metronidazole IV is state-determined and often based on the state’s drug pricing methodology (typically a percentage of the drug’s AWP, WAC, or ASP). Private payer rates vary by contract. Providers should not assume a prior S0030 reimbursement rate applies to J0694; a separate fee schedule verification is required for each payer. The PGM Billing HCPCS lookup tool provides free access to CMS HCPCS data and can help billing teams confirm a code’s attributes before submission.

Infusion clinics should also consider whether administration codes apply alongside the drug code. CPT codes for therapeutic drug infusion (such as 96365 for the initial hour of non-chemotherapy drug infusion) may be billed separately when metronidazole is administered as an infusion rather than a push. The drug code and the infusion administration code together represent the complete service. Tracking both components in a structured billing workflow reduces the risk of undercoding the full encounter.

Pabau’s claims management software supports multi-line drug and administration code billing so infusion clinics can capture every billable component of a treatment visit.

Conclusion

HCPCS code S0030 is a deleted temporary national code for metronidazole 500 mg injection that no longer appears in the active CMS HCPCS file. Billing staff encountering this code on older contracts or remittances should substitute J0694 as the current crosswalk for most payer submissions, or J3490 only when a specific code is unavailable or a payer explicitly requires an unclassified drug code.

Medicare does not cover any S-code, and Medicaid coverage requires state-level verification of the current replacement code. Accurate NDC reporting, correct unit billing, and pre-submission payer verification are the three practices that prevent the most common drug injection claim errors.

For infusion clinics and IV therapy practices managing a high volume of drug injection claims, keeping code crosswalks current and tracking NDC requirements by payer is a significant administrative burden. Pabau’s medical billing software integrates charge capture, drug coding, and payer-specific requirements so billing teams can manage billing workflows without switching between multiple reference systems.

To see how Pabau handles drug injection billing for outpatient and infusion clinics, book a demo.

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