When you’re working with an out-of-network patient under a Single Case Agreement (SCA), everything depends on getting the claim submitted correctly. The SCA gives you permission to treat the patient, but the claim won’t process unless the number is placed in the right spot on the CMS-1500 form. A small mistake can slow the payment down or push it into a denial pile.

The good news is that you don’t need complex billing knowledge to get this part right. You just need to know where the SCA number belongs, how to format it, and what supporting details the payer expects. Think of this guide as the simple walkthrough you wish someone had given you on day one.

What the SCA Number Actually Does

A Single Case Agreement number works like a bridge between you and the insurance plan. Since you’re not in the network, the SCA tells the insurer to treat your claim differently from a normal out-of-network claim. Without this number, the claim looks like any other non-contracted bill, which means it may get denied or paid at the lowest possible rate.

The SCA number is the key that tells the system: Pay this claim as agreed under the special arrangement.That’s why putting it in the right field is so important.

Where the SCA Number Goes on a CMS-1500 Claim Form

The CMS-1500 claim form has many boxes, but only one is used to report a Single Case Agreement number:

Box 19 – Additional Claim Information

This is the official location where payers look for SCA details.
Most insurers require the information in this format:

SCA – Ref # [your assigned number]

That’s it.
Short, clear, and precise.

Enter it exactly this way unless the payer gives another specific instruction. Some payers may ask you to write Agreement Number, Reference Number, or Case Authorization, but nearly all accept the standard SCA label.

What to Include Along With the SCA Number

Here’s what most payers expect inside Box 19:

• The Single Case Agreement number

• Any related reference or approval codes

• A brief note like Per SCA or Authorized under SCA

• The date the agreement became effective, if required

Don’t add CPT codes or long explanations. Box 19 is not a note field for clinical details—only for special claim identifiers.

This matters even more for teams handling ABA therapy billing services, since SCA cases often involve children who need ongoing care. When the number is missing or entered incorrectly, treatment interruptions happen because the claims don’t process the way they should. A clean claim avoids that.

Step-by-Step: How to Add the SCA Number Correctly

Follow these steps each time you submit a claim under a Single Case Agreement:

Step 1: Locate the written SCA approval

Find the approval letter or email from the payer. The SCA number is usually near the top or next to the authorized CPT codes.

Step 2: Verify the exact spelling and formatting

Some payers use dashes, some use letters combined with numbers. Copy it exactly as given.

Step 3: Open the CMS-1500 form

Whether you submit manually or through a billing system, the SCA number must appear in Box 19.

Step 4: Enter the line

Example:
SCA – Ref # xxxxxxx

Step 5: Double-check for errors

One wrong digit can send the claim into out-of-network denial processing.

Step 6: Submit as usual

Use the CMS-1500 as you normally would for coding and reimbursement.

This process stays the same across most specialties, including mental health, physical therapy, speech therapy, and clinics offering ABA billing services where SCA requests are common when families switch plans or face long waitlists.

Common Mistakes to Avoid

Even experienced billers slip up on SCAs. Here are errors that slow down payments:

1. Leaving Box 19 blank

Without the SCA number, the payer has no way to match the claim to the agreement.

2. Putting the number in the wrong box

Box 23 (prior authorization) is not the right place. SCAs are not standard authorizations.

3. Using the patient’s name instead of the reference number

Only the official SCA identifier counts.

4. Entering long sentences

Box 19 is not meant for lengthy notes. Keep it short.

5. Forgetting the label “SCA”

Your claim may be processed incorrectly if you don’t label the number.

Why Proper Placement Matters for Payment

A clean claim means fewer delays and less back-and-forth with the payer. When the SCA number is in the correct place:

• Claims route to the right payer department

• Adjusters know to apply the SCA rate

• Denials decrease

• Families avoid unexpected bills

• Your team avoids unnecessary appeals

For many clinics, the SCA becomes the only way to keep care consistent during insurance transitions. Correct billing keeps everything moving smoothly.

FAQs

1. Can I put the SCA number in Box 23 instead of Box 19?

No. Box 23 is for prior authorizations. A Single Case Agreement is different, even though it functions similarly. Always use Box 19.

2. What if the payer gives me more than one reference number?

Add the primary SCA number first. If space allows, you can include the second number on the same line.

3. Do I need to add the SCA number for every claim?

Yes. Each visit under the Single Case Agreement must list the reference number.

4. What happens if the SCA number is wrong or missing?

The insurance company may process your claim as out-of-network and pay a reduced amount or deny the claim entirely.

5. Do SCA claims require modifiers?

Use modifiers only if the payer’s rules require them for the CPT codes. The SCA number does not replace standard coding rules.

6. Do I still need progress notes with an SCA?

Absolutely. An SCA does not remove documentation requirements. Notes must still support medical necessity.

Conclusion

Adding a Single Case Agreement number to a CMS-1500 claim form is a simple step that has a big impact. When the number is placed correctly in Box 19, the payer can link your claim to the approved agreement and reimburse you at the negotiated rate. When it’s missing or entered wrong, the claim takes a completely different path—usually toward denial or reduced payment.

By understanding what the SCA number does, where it belongs, and how to format it, you make the billing process smoother for your team and the families you serve. A clear process protects your revenue, supports continuity of care, and keeps claims moving without interruptions.