# Coordination of benefits (COB) checks
Source: https://www.stedi.com/docs/healthcare/coordination-of-benefits

***

title: Coordination of benefits (COB) checks
sidebarTitle: "Coordination of benefits checks"
-----------------------------------------------

Some patients have multiple health plans. For example, a dependent may have coverage with two private insurance companies through their parents. When a patient has active coverage with multiple plans, you need to know which health plan is primarily responsible for paying claims (coordination of benefits).

You can use a coordination of benefits (COB) check to determine:

* If a patient is covered by more than one health plan
* Whether there is coverage overlap between plans
* Whether coverage overlap requires coordination of benefits
* Each payer's responsibility for payment (primacy) in coordination of benefits scenarios

COB checks can help ensure that you submit claims to the correct payer and avoid claim denials. We recommend performing COB checks for all new patients who have coverage through one of Stedi’s supported payers. When Stedi identifies overlapping coverage, we strongly recommend performing follow-up [eligibility checks](/healthcare/send-eligibility-checks) with each payer to verify coverage status and retrieve the patient's complete and current benefits information before you submit claims.

<Tip>
  COB checks require that you know at least one of the patient's active health
  plans. If you're unsure whether a patient has any active coverage at all, you
  can perform an [insurance discovery check](/healthcare/insurance-discovery) to
  find potential coverage.
</Tip>

## Supported payers

COB doesn't support Medicare plans. However, most Medicare Advantage plans are supported. Visit the [Payer Network](https://www.stedi.com/healthcare/network?query=eyIyNzAiOnt9LCIyNzYiOnt9LCI4MzUiOnt9LCI4MzdQIjp7fSwiODM3SSI6e30sIjgzN0QiOnt9LCJDT0IiOnsiaXNTdXBwb3J0ZWQiOnRydWV9fQ%3D%3D\&page=0) for a complete list of supported payers.

## Transaction enrollment

[Transaction enrollment](/healthcare/transaction-enrollment) isn't required to run COB checks through Stedi.

## How COB checks work

You submit a coordination of benefits request with information for one of the patient's health plans. The information required is similar to a standard eligibility check – first name, last name, DOB, and either member ID or SSN – and you should first run a [real-time eligibility check](https://www.stedi.com/docs/healthcare/api-reference/post-healthcare-eligibility) to ensure that the member’s details are accurate.

Once you submit the request, Stedi searches a database of eligibility data from regional and national plans. This database has 245+ million patient coverage records from 45+ health plans, ASOs, TPAs, and others, including participation from the vast majority of national commercial health plans. Data is updated at least weekly to ensure accuracy.

Stedi synchronously returns summary information about each of the patient’s active health plans, whether there is coverage overlap, and, if so, the responsibility sequence number for each payer (such as primary or secondary, if that can be determined).

Once you receive the results, we strongly recommend performing follow-up [eligibility checks](/healthcare/send-eligibility-checks) with each payer to verify coverage status and retrieve the patient's complete and current benefits information before you submit claims.

## Check COB

Each COB check must be for a participating health plan for which the patient has coverage. For example, if the patient has coverage from Cigna and UnitedHealthcare, a COB check to Aetna will return an error.

<Note>Medicare and Medicare Advantage plans are not supported.</Note>

### Accurate patient data

COB checks are significantly more sensitive to data accuracy than eligibility checks. To perform successful COB checks, the patient information you provide in the check **must** match the payer's data exactly.

For example, if a payer has a patient's name stored as "Jonathan Doe", they may return benefits information when you submit an eligibility check for "Jon Doe", as long as they can identify the patient through the other information provided. However, a COB request for "Jon Doe" will fail because the name doesn't match the payer's records exactly.

To avoid unnecessary COB check failures, we strongly recommend that you first submit an eligibility check request for the patient. Then use the following data from the successful eligibility response to build the COB request: `firstName`, `lastName`, `dateOfBirth`, `memberId`.

### Service type code

You can submit COB checks with the `30` service type code for Health Benefit Plan Coverage. This is the broadest service type code that covers all medical services and subtypes included in the patient's health plan.

### API submission

Use the [Coordination of Benefits Check](/healthcare/api-reference/post-coordination-of-benefits) endpoint to submit COB checks programmatically. The information required in the request is similar to a standard eligibility check – first name, last name, DOB, and either member ID or SSN.

The following example shows a COB check for a dependent named Jordan Doe who has coverage with Blue Cross Blue Shield of Massachusetts (Stedi payer ID: `EWDCI`).

```bash
curl --request POST \
  --url "https://healthcare.us.stedi.com/2024-04-01/coordination-of-benefits" \
  --header "Authorization: <api_key>" \
  --header "Content-Type: application/json" \
  --data "'{
    "tradingPartnerServiceId": "EWDCI",
    "provider": {
      "organizationName": "ACME Health Services",
      "npi": "1999999984"
    },
    "subscriber": {
      "firstName": "John",
      "lastName": "Doe",
      "dateOfBirth": "1985-05-27",
      "memberId": "W000000000"
    },
    "dependent": {
      "firstName": "Jordan",
      "lastName": "Doe",
      "dateOfBirth": "2002-12-31"
    },
    "encounter": {
      "dateOfService": "2024-08-02",
      "serviceTypeCode": "30"
    }
  }'"
```

Visit [Request and response examples](/healthcare/cob-response#request-and-response-examples) to review sample COB checks for common scenarios.

#### Concurrency limit

Visit [Concurrency limits](/healthcare/api-reference#concurrency-limits) for more information.

### Manual submission

To prevent accidentally sending checks to unsupported payers, the Stedi portal only provides the option to perform a COB check within successful eligibility checks to supported COB payers.

To submit a new COB check through the Stedi portal:

1. Go to the [Eligibility searches](https://portal.stedi.com/app/healthcare/eligibility) page.
2. Click the eligibility check for the patient you want to check for coordination of benefits. This must be a successful eligibility check for the patient's health plan - failed checks can't be used as the basis for COB checks.
3. Click **View** to review the details of the eligibility check.
4. Click `New COB check` to open the coordination of benefits check form. Stedi prefills the patient's information from the eligibility check.