How to Fill Out the Washington Medicaid Prior Authorization Form (HCA 13-835)

To fill out the Washington Medicaid prior authorization form HCA 13-835, type every field (handwriting is not accepted), use the Apple Health client ID and NPIs in the correct boxes, enter the right code qualifier and national code for the service you’re requesting, and attach clinical documentation that lines up with the Health Care Authority’s billing guide for your program. Then submit through the ProviderOne portal or by fax to 1-866-668-1214 with a barcode cover sheet.¹

The form has four blocks: client information, provider information, service request details, and medical information. Each has a few fields that reviewers will not process without, and a few that are optional but worth including.

Before You Start: Confirm You’re Using the Right Form

The standard HCA 13-835 covers almost every type of prior authorization request. Pharmacy point-of-sale requests use a separate companion form, the HCA 13-835A. Download the current PDF from the Health Care Authority’s forms and publications search, or access it through the ProviderOne portal.²

One boundary worth checking first: if your patient is enrolled in a managed care organization like Molina, UnitedHealthcare, or Coordinated Care rather than fee-for-service Apple Health, the HCA 13-835 is not the right form. Each MCO uses its own template and maintains its own list of services that need prior authorization. Verify the patient’s coverage source and use the form that matches it.

Client and Provider Fields

The instructions on the form require that all fields be typed. Handwritten submissions are rejected.¹

Field 1, Org: the number for the program or unit handling the request. This routes the form to the correct review team.
Field 2, Service Type: the letter code (in all caps) that represents the type of service.
Field 3, Name: the patient’s last name, first name, and middle initial.
Field 4, Client ID: the patient’s Apple Health ID, which is nine digits followed by “WA.”
Field 5, Living Arrangements: where the patient resides, such as home, group home, assisted living, or skilled nursing facility.
Field 6, Reference Auth #: fill this in only if you’re requesting a change or extension to an existing authorization.
Field 7, Requesting NPI: the ten-digit National Provider Identifier for the requesting provider.
Field 9, Billing NPI: the ten-digit NPI for the billing provider, which may differ from the requesting provider.

Fields 8, 10, 11, and 12 cover the requesting provider’s fax number and the billing and referring provider details. These are not all strictly required, but entering a fax number gives reviewers a fast way to reach your office if they need more information before deciding.¹

Service Request and Medical Fields

This is where most errors happen, because the coding fields have strict format rules.

Field 15, Description: a short plain-language description of what you’re requesting.
Field 20, Code Qualifier: a single letter indicating the coding system. Use C for CPT, P for HCPCS, I for ICD-9/10 diagnosis, T for CDT dental codes, D for DRG, R for revenue code, or S for ICD-9/10 procedure code.
Field 21, National Code: the specific service code that goes with the qualifier you chose in Field 20.
Field 23, Units/Days Requested: the number of units or days, for items with a set allowable amount.
Field 24, Dollar Amount Requested: for codes without a set allowable, enter the amount in dollars and cents with a decimal, for example 400.00.
Field 27, Diagnosis Code: the ICD-10 code for the patient’s condition.
Field 28, Diagnosis Name: a short description of the diagnosis.
Field 29, Place of Service: the two-digit place-of-service code.

Some service types need extra fields. Durable medical equipment requests must include Field 18 (equipment serial number or NEA/MEA number) and Field 25 (manufacturer part number). Dental requests need the tooth or quadrant number in Field 26.¹

Field 14: The Expedite Flag

Mark “Yes” in Field 14 only when the patient’s health, life, or ability to regain function would be at risk under the standard review timeline. Flagging a routine request as expedited will not speed it up. Reviewers apply the same medical necessity standard either way.

Attach the Clinical Documentation

The form itself rarely tells reviewers enough. Attach recent chart notes, imaging reports, lab results, and anything else that connects the patient’s condition to the specific service you’re requesting. A letter of medical necessity from the treating provider is often the clearest way to bridge the diagnosis and the request, especially for equipment or procedures that have multiple clinical criteria to satisfy.

What counts as “enough” documentation depends on the Health Care Authority’s billing guide for the program area the service falls under. Reviewers compare your packet against those published criteria point by point. Pulling up the current billing guide before assembling the submission is the single best way to avoid a pend request for more information.

How to Submit the Completed Form

You have two channels: direct data entry through the ProviderOne portal, or fax.

ProviderOne (Direct Data Entry)

ProviderOne lets you enter the request directly and upload clinical records, color photos, and x-rays. You sign in through OneHealthPort’s single sign-on page with a subscriber ID and password.³ After a successful submission, the system returns a nine-digit reference number as proof of receipt. If the authorization is later pended for additional documents, you can upload them through the portal without a barcode cover sheet.²

HCA publishes separate DDE training guides for dental, medical, and DME providers on the prior authorization page of its website. Working through the right guide before your first submission heads off most formatting problems.

Fax

Fax the completed form and backup documents to 1-866-668-1214. Use the HCA barcode cover sheet as the first page so the system links your pages to the correct patient file. If your browser can’t generate the barcode, enter the TCN or prior authorization number on the cover sheet and still use it as page one.⁴ Barcode cover sheets are no longer required for pharmacy point-of-sale prior authorization requests.

What Happens Next

For fee-for-service Apple Health, HCA has fifteen days from receipt to approve, deny, or request more information. If reviewers ask for additional documentation, you have thirty days to send it. HCA then has five business days after receiving your materials to issue a final decision. Miss the thirty-day window and the request is denied.⁵

When a request is approved, you receive an authorization number. That number must appear on the claim you later submit for payment. Do not perform the procedure or bill for it until the written approval comes back; claims submitted without an approved authorization are typically denied.²

Expedited requests move much faster. Electronic submissions through the web portal get a one-calendar-day turnaround, and faxed expedited requests get two calendar days. If a denial comes back, the written notice to the patient and provider will spell out the factual basis, the WAC provision the decision rests on, and the patient’s appeal rights.⁵

1
Washington State Health Care Authority. General Information for Authorization – HCA 13-835
2
Washington State Health Care Authority. Step-by-Step Guide for Prior Authorization
3
Washington State Health Care Authority. Accessing ProviderOne Through OneHealthPort
4
Washington State Health Care Authority. Document Submission Cover Sheets
5
Washington State Legislature. WAC 182-501-0165 – Prior Authorization