(1) A child, youth, or family with a current address in Washington state is eligible for services if the child or youth is younger than eighteen years of age, and has one or more of the following:

(a) A disability or disabling condition(s);

(b) Chronic illness or condition(s);

(c) Health-related educational or behavioral condition(s); or

(d) A risk of developing disabilities, chronic conditions, or health-related educational and behavioral conditions.

For the purposes of subsection (1) of this section, length of stay in the state is not considered in determining residency.

(2) Financial eligibility is not considered in determining client eligibility for the CYSHCN program except as outlined in subsection (3) of this section regarding DX/TX funds.

(3) Some services may be covered for established clients who are eighteen to twenty-one years of age, provided that the service or treatment:

(a) Was previously planned as a continued stage of treatment required to achieve health goals;

(b) Was initiated before the client turned eighteen;

(c) Has a definable treatment course with a clear end point; and

(d) Will not be authorized after a client's twenty-first birthday.

(4) A client may, at the discretion of the department, be eligible for DX/TX funds if they meet either of the following:

(a) Eligible for medicaid without monthly premiums; or

(b) Have current eligibility approved by the HCA-medicaid program, or the women, infants, and children program.

(5) A client shall request and the department shall determine DX/TX financial eligibility annually.

(6) DX/TX funds are not an entitlement. DX/TX funds are subject to medical necessity review by the local CYSHCN agency and availability of funding. The department may reduce the scope of CYSHCN services and impose or revise funding limitations on certain services when required for any reason including, but not limited to, budgetary reasons.

(7) For the purposes of this section, "medical necessity" means services which are reasonably calculated to prevent, diagnose, correct, cure, alleviate, or prevent worsening of conditions that endanger life, cause suffering or pain, result in illness or infirmity, threaten to cause or aggravate a disability or health condition, for which there is no other equally effective, more conservative, or substantially less costly course of treatment available or suitable for the client. For the purposes of this definition, a course of treatment may include treatment, observation, or no treatment at all.