STCs and procedure codes

You're likely running an eligibility check to determine the patient's coverage and financial responsibility for particular medical or dental services, such as chiropractic or hospice care.

You can retrieve specific types of benefits information from the payer by including either a service type code (STC) or a procedure code and qualifier in your request.

However, it's not always clear which STC or procedure code to use for best results. This page explains how to choose the right STC or procedure code for your eligibility check, how to test whether a payer supports a specific STC, and how to map procedure codes to STCs when necessary.

Should I use STCs or procedure codes?

It depends on the type of benefits information you want to retrieve.

Medical benefits

You'll almost always need to submit an STC because most medical payers don't support procedure codes (CPT/HCPCS/CDT). Refer to our guidance for choosing STCs.

Dental benefits

Many (but not all) dental payers support procedure codes. However, we recommend:

1. First try STC 35 - especially if you need information about general dental benefits. Many payers only return comprehensive dental-specific benefits for STC 35.
2. Try the relevant CDT code if you still need more benefits information for a specific service.
3. If the CDT code still doesn't return what you need, try the STC mapped to that CDT code. Refer to our list of common mappings for dental benefits.

Choose the right STC

A Service Type Code (STC) is a two-character code that groups similar healthcare services into standard categories, such as 47 (Hospital) and UC (Urgent Care). STC support varies by payer:

• Not all payers support all STCs.
• Some payers only respond to the first STC you send and ignore the rest.
• Some payers completely ignore the STCs in the request and always return a default response for STC 30 (Health Benefit Plan Coverage).
• Some payers don't support multiple STCs in a single request.
• Some payers do support multiple STCs, but only a limited number per request.

When choosing an STC, we recommend:

• Send the most specific STC you can for the services you're targeting. You should test the STCs that seem most appropriate to determine which ones yield the most benefits information. Refer to our list of STCs for common services.
• If no specific STC seems appropriate or if the payer doesn't support it, fall back to a general benefit check.
• Include only one STC per request, unless you've tested the payer and confirmed they support multiple STCs in a single request and that the response contains better benefits information when you include more than one.

If after testing, no STC produces the benefits information you need, you may need to call the payer or visit the payer portal.

General benefit checks

Use STC 30 for general medical benefits or 35 for general dental benefits. These STCs are supported by all payers and are a good fall back when a payer doesn't support a more specific STC.

When you send STC 30 in an eligibility check, all payers must return benefits information for the following STCs when the patient's plan covers them:

• 1 (Medical Care)
• 33 (Chiropractic)
• 47 (Hospital)
• 86 (Emergency Services)
• 88 (Pharmacy)
• 98 (Professional Physician Visit - Office)
• AL (Vision - Optometry)
• MH (Mental Health)
• UC (Urgent Care)

CAQH CORE-certified payers are required to support a broader set of STCs.

STCs for common services

Try the following STCs in the order shown - from the most specific to more general alternatives. We recommend sending only one STC at a time, unless you've tested the payer and confirmed they support multiple in a single request.

We've also included the mapping to specific procedure codes where possible, to make it easier to determine the right STC for your use case. Ranges of applicable codes are represented as rangeStart - rangeEnd.

Medical

Procedure codes	Type of care	STCs to try
97151 - 97157	ABA Therapy	BD, MH
97810, 97811 - 97814	Acupuncture	64, 1
96401 - 96549	Chemotherapy	ON, 82, 92
96493	Chemotherapy, IV push	82, 92
96494	Chemotherapy, additional infusion	82, 92
99490, 99439, 99491, 99437, 99487	Chronic Care Management (CCM) services	A4, MH, 98, 1
too many to list	Dermatology	3, 98
E1399	Durable Medical Equipment	DM, 11, 12, 18
96375	IV push	92
96360, 96365, 96366	IV Therapy/Infusion	92, 98
too many to list	Maternity (professional)	BT, BU, BV, 69
97802	Medical nutrition therapy	98, MH, 1
97803	Medical nutrition follow-up	98, MH, 1
too many to list	Mental health	MH, 96, 98, A4, BD, CF
95700 - 96020	Neurology	98
99460, 99463	Newborn/facility	65, BI
97165 - 97168 and 97110, 97530, 97112, 97140, 97535, 97116, 97129	Occupational therapy	AD, 98
97110, 97112, 97116, 97350, and several others	Physical therapy	PT, AE
too many to list	Podiatry	93, 98
too many to list	Primary care	96, 98, A4, A3, 99, A0, A1, A2, 98
99214	Psychiatry visits	A4, MH
96130	Psychological testing evaluation	A4, MH
90832, 90834, 90837, 90833, 90836, 90838, 90839, 90846, 90847, 90849	Psychotherapy	96, 98, A4, BD, CF
too many to list	Rehabilitation	A9, AA, AB, AC
98975, 98976, 98977, 98980, 98981	Remote Therapeutic Monitoring (RTM) services	A4, 98, MH, 92, DM, 1
99304-99318	Skilled Nursing	AG, AH
92507, 92508, 92521, 92522, 92523, 92526, 92607, 92609, 92605, 92618	Speech Therapy	AF, 98
90791, 90832, 90834, 90837, 90853, 99408, 99409, and H0017-H0019	Substance Abuse/Addiction	AI, AJ, AK, MH
99202-99215, 99421-99423, 99441-99443, G2010 and G2012	Telehealth	9, 98
90867	Transcranial magnetic stimulation	A4, MH

Dental

Procedure	Type of care	STCs to try
D4210	Gingivectomy or gingivoplasty	25
D4381	Local delivery of antimicrobial agent	25
D5110	Complete maxillary (upper) denture	39

Full STC list

You can include the following STCs in an eligibility check. Not all payers support all STCs, so you should always test each payer to ensure they support the STCs you plan to use.

• The word physician in service type codes refers to any healthcare provider, including physician assistants, nurse practitioners, and other types of healthcare professionals.
• Don't send STCs that aren't in this list. This list is specific to X12 version 005010, the mandated version for eligibility checks. It's different from the X12 Service Type Codes list, which applies to X12 versions later than 005010. Payers shouldn't accept or send STCs not explicitly listed in version 005010.

Test payer STC support

We recommend testing each payer to determine which STC(s) they support and which STC(s) return the most benefits information for the services you care about.

To test whether a payer supports a specific STC:

1. Send a baseline request with just STC 30 for general medical benefits or 35 for general dental benefits.
2. Send a request with the specific STC that best matches the benefit type you want to check. For example, to check mental health benefits, you might send a request with STC MH (Mental Health). Use our list of STCs for common services as a starting point.
3. Compare the baseline response with the response to the specific STC. If they're different, the payer likely supports the specific STC.

You may also want to test whether the payer supports multiple STCs in a single request:

1. Send a baseline request with just STC 30 for general medical benefits or 35 for general dental benefits.
2. Send a request with multiple STCs matching the benefit types you want to check.
3. Compare the responses. If they change based on the number of STCs, the payer likely supports multiple STCs in a single request. If not, the payer may be ignoring or only partially supporting STCs - for example, they may only be returning information for the first STC.

We recommend scripting your requests to speed up the testing process. Specifically, you should loop through candidate STCs and compare the responses against the baseline STC 30 or 35 response for the same patient. You can also save the benefitsInformation array for each STC and diff them. This approach helps you more easily identify changes between test requests.

Map procedure codes to STCs

It can be hard to map procedure codes to the right STC. For example, if a provider offers medical nutrition therapy and bills using CPT code 97802, should they use service type code 1 - Medical Care, 3 - Consultation, MH - Mental Health, or another option?

Unfortunately, there's no standardized mapping between procedure codes and STCs. In fact, payers themselves often don't have an explicit mapping for their own health plans. Their eligibility check systems aren't necessarily directly integrated with their claims processing systems, so when you ask them which STC to use, they may not always be able to provide a good answer.

Review our list of STCs for common services, which contains mappings to the associated procedure codes. If you don't find the procedure code you're looking for, use the following approaches to determine the best STC for your use case:

• Review the payers' documentation for eligibility checks. Some payers provide a list of STCs they support and their mappings to procedure codes.
• If you can't find the information in the payer's documentation, contact the payer directly or reach out to Stedi support, and we'll contact the payer for you.
• For dental payers that don't support specific CDT codes, you can use either of these sources to map CDT codes to service type codes. You can either purchase a copy of these documents or contact Stedi support for recommendations about specific mappings:
  • NDEDIC's Companion to ASC X12 270/271
  • Table 6 in the American Dental Association's Technical Report No. 1102.
• If none of the above methods work, you can ask a medical coder with AAPC certification for guidance. Their familiarity with billable codes will help them make good recommendations about service type code mappings.

Once you determine the right STC code(s), we recommend maintaining an internal document that contains the mappings for the health plans you most frequently bill.

Required STCs for CORE-Certified payers

CAQH CORE creates operating rules and frameworks that improve interoperability in healthcare data exchange. CORE requires certified payers to support a broader set of STC codes than those mandated for general benefits inquiries.

If the plan covers the service, certified payers must return benefit information for the following STCs. Visit CAQH CORE's website for a complete list of CORE-Certified Health Plans.

STCs in the eligibility response

To determine whether the payer is returning the benefits information you need, you must check the benefitsInformation array. Each object in this array contains a serviceTypeCodes property that lists the applicable STCs.

The payer may send benefits information for additional STCs you didn't request - this is expected. It can also mean that the payer is ignoring the STC you sent, which is why we recommend testing payers to determine their support for specific STCs.

The following example shows a benefitsInformation object that specifies a patient's co-payment ($20) for psychiatric, psychotherapy, and social work in-office visits.

{
  "code": "B",
  "name": "Co-Payment",
  "coverageLevelCode": "IND",
  "coverageLevel": "Individual",
  "serviceTypeCodes": ["A4", "A6", "22"],
  "serviceTypes": ["Psychiatric", "Psychotherapy", "Social Work"],
  "timeQualifierCode": "27",
  "timeQualifier": "Visit",
  "benefitAmount": "20",
  "authOrCertIndicator": "N",
  "inPlanNetworkIndicatorCode": "Y",
  "inPlanNetworkIndicator": "Yes",
  "eligibilityAdditionalInformation": {
    "codeListQualifierCode": "ZZ",
    "industryCode": "Office"
  },
  "eligibilityAdditionalInformationList": [
    {
      "codeListQualifierCode": "ZZ",
      "industryCode": "Office"
    }
  ]
}

You should review the STC list to determine which STCs are relevant to the benefits you're interested in and check for all of them in the response. This is helpful because the payer may return relevant benefits under a different STC than the one you submitted. For example, mental health benefits are typically returned with STC MH (Mental Health), but some payers may use other STCs, such as BH (Behavioral Health), A4 (Psychiatric) or SA (Substance Abuse) for related services.

You should also check all benefitsInformation objects with relevant serviceTypeCodes values because the same STC is typically repeated across multiple benefitsInformation objects in the response.

• Each object communicates a different aspect of benefits, such as coverage status, co-pays, or deductibles.
• Payers also use multiple objects to describe different subsets of services within an STC. For example, the MH STC might have one entry for standard therapy and another that notes coverage for other treatments. Descriptions typically appear in entries with code: "1" (Active Coverage) or code: "D" (Benefit Description), but they can appear in other entries as well.

To learn more about interpreting the eligibility response, visit Determine patient benefits.