The agency uses eight steps to calculate a person's risk score.

1. (1) Step 1. Collect paid claims and health plan encounter data. The agency obtains a set of paid fee-for-service claims and managed care encounters for a client.

   1. (a) For clients age 17 and younger, the agency uses all paid claims and encounters within the last 24 months.

   2. (b) For clients age 18 and older, the agency uses all paid claims and encounters within the last 15 months.

      1. (i) The claims and encounters include the international classification of diseases (ICD) diagnosis codes and national drug codes (NDC) submitted by health care providers. These are used in steps 2 and 3 to create a set of risk categories.

      2. (ii) The agency uses two algorithms developed by the University of San Diego:

         1. (A) Chronic illness and disability payment system (CDPS) which assigns ICD diagnosis codes to CDPS risk categories (see Table 3 in subsection (5)(b) of this section); and
         2. (B) Medical Rx (MRx) which assigns NDCs to MRx risk categories (see Table 2 in subsection (3)(b) of this section).

2. (2) Step 2. Group ICD diagnosis codes into chronic illness and disability payment system risk categories.

   1. (a) To group ICD diagnosis codes into the CDPS risk categories (see Table 1 in (b) of this subsection), the agency uses an ICD diagnosis code to CDPS risk categories crosswalk in subsection (1)(b)(ii)(A) of this section. Each of the ICD diagnosis codes listed is assigned to one risk category. If an ICD diagnosis code is not listed in the crosswalk it does not map to a risk category that is used in the calculation of the risk score.

   2. (b) Table 1. Titles of Chronic Illness and Disability Payment System Risk Categories

      CARVH	Cardiovascular, very high
      CARM	Cardiovascular, medium
      CARL	Cardiovascular, low
      CAREL	Cardiovascular, extra low
      PSYH	Psychiatric, high
      PSYM	Psychiatric, medium
      PSYML	Psychiatric, medium low
      PSYL	Psychiatric, low
      SKCM	Skeletal, medium
      SKCL	Skeletal, low
      SKCVL	Skeletal, very low
      CNSH	Central Nervous System, high
      CNSM	Central Nervous System, medium
      CNSL	Central Nervous System, low
      PULVH	Pulmonary, very high
      PULH	Pulmonary, high
      PULM	Pulmonary, medium
      PULL	Pulmonary, low
      GIH	Gastro, high
      GIM	Gastro, medium
      GIL	Gastro, low
      DIA1H	Diabetes, type 1 high
      DIA1M	Diabetes, type 1 medium
      DIA2M	Diabetes, type 2 medium
      DIA2L	Diabetes, type 2 low
      SKNH	Skin, high
      SKNL	Skin, low
      SKNVL	Skin, very low
      RENEH	Renal, extra high
      RENVH	Renal, very high
      RENM	Renal, medium
      RENL	Renal, low
      SUBL	Substance abuse, low
      SUBVL	Substance abuse, very low
      CANVH	Cancer, very high
      CANH	Cancer, high
      CANM	Cancer, medium
      CANL	Cancer, low
      DDM	Developmental Disability, medium
      DDL	Developmental Disability, low
      GENEL	Genital, extra low
      METH	Metabolic, high
      METM	Metabolic, medium
      METVL	Metabolic, very low
      PRGCMP	Pregnancy, complete
      PRGINC	Pregnancy, incomplete
      EYEL	Eye, low
      EYEVL	Eye, very low
      CERL	Cerebrovascular, low
      AIDSH	AIDS, high
      INFH	Infectious, high
      HIVM	HIV, medium
      INFM	Infectious, medium
      INFL	Infectious, low
      HEMEH	Hematological, extra high
      HEMVH	Hematological, very high
      HEMM	Hematological, medium
      HEML	Hematological, low

3. (3) Step 3. Group national drug codes (NDCs) into MRx risk categories.

   1. (a) To group the NDC codes into MRx risk categories (see Table 2 in (b) of this subsection), the agency uses a NDC code to MRx risk categories crosswalk in subsection (1)(b)(ii)(B) of this section.

   2. (b) Table 2. Titles of Medicaid Rx Risk Categories

      MRx1	Alcoholism
      MRx2	Alzheimer's
      MRx3	Anti-coagulants
      MRx4	Asthma/COPD
      MRx5	Attention Deficit
      MRx6	Burns
      MRx7	Cardiac
      MRx8	Cystic Fibrosis
      MRx9	Depression/Anxiety
      MRx10	Diabetes
      MRx11	EENT
      MRx12	ESRD/Renal
      MRx13	Folate Deficiency
      MRx14	CMV Retinitis
      MRx15	Gastric Acid Disorder
      MRx16	Glaucoma
      MRx17	Gout
      MRx18	Growth Hormone
      MRx19	Hemophilia/von Willebrands
      MRx20	Hepatitis
      MRx21	Herpes
      MRx22	HIV
      MRx23	Hyperlipidemia
      MRx24	Infections, high
      MRx25	Infections, medium
      MRx26	Infections, low
      MRx27	Inflammatory/Autoimmune
      MRx28	Insomnia
      MRx29	Iron Deficiency
      MRx30	Irrigating Solution
      MRx31	Liver Disease
      MRx32	Malignancies
      MRx33	Multiple Sclerosis/Paralysis
      MRx34	Nausea
      MRx35	Neurogenic Bladder
      MRx36	Osteoporosis/Pagets
      MRx37	Pain
      MRx38	Parkinsons/Tremor
      MRx39	Prenatal Care
      MRx40	Psychotic Illness/Bipolar
      MRx41	Replacement Solution
      MRx42	Seizure Disorders
      MRx43	Thyroid Disorder
      MRx44	Transplant
      MRx45	Tuberculosis

4. (4) Step 4. Remove duplicate risk categories. After mapping all diagnosis and drug codes to the risk categories, the agency eliminates duplicates of each client's risk categories so that there is only one occurrence of any risk category for each client.

5. (5) Step 5. Select the highest CDPS risk category within a disease group.

   1. (a) The agency organizes CPDS risk categories into risk category groups of different intensity levels. The high risk category in each group is used in the calculation of the risk score. The lower level risk categories are eliminated from further calculations.

   2. (b) Table 3. Chronic Disease Payment System Risk Category Groups

      Group Description	Risk Categories (Ordered Highest to Lowest Intensity)
      AIDS/HIV and Infection	AIDSH, INFH, HIVM, INFM, INFL
      Cancer	CANVH, CANH, CANM, CANL
      Cardiovascular	CARVH, CARM, CARL, CAREL
      Central Nervous System	CNSH, CNSM, CNSL
      Diabetes	DIA1H, DIA1M, DIA2M, DIA2L
      Developmental Disability	DDM, DDL
      Eye	EYEL, EYEVL
      Gastrointestinal	GIH, GIM, GIL
      Hematological	HEMEH, HEMVH, HEMM, HEML
      Metabolic	METH, METM, METVL
      Pregnancy	PRGCMP, PRGINC
      Psychiatric	PSYH, PSYM, PSYML, PSYL
      Substance Abuse	SUBL, SUBVL
      Pulmonary	PULVH, PULH, PULM, PULL
      Renal	RENEH, RENVH, RENM, RENL
      Skeletal	SKCM, SKCL, SKCVL
      Skin	SKNH, SKNL, SKNVL

6. (6) Step 6. Determine age/gender category.

   1. (a) For each client, the agency selects the appropriate age/gender category. The 11 categories are listed in Table 4 in (b) of this subsection. The categories for ages below five and above 65 are gender neutral.

   2. (b) Table 4. Age/Gender Categories

      Age	Gender
      	Age <1
      	Age 1 to 4
      	Age 5 to 14		Male
      	Age 5 to 14		Female
      	Age 15 to 24		Male
      	Age 15 to 24		Female
      	Age 25 to 44		Male
      	Age 25 to 44		Female
      	Age 45 to 64		Male
      	Age 45 to 64		Female
      	Age 65+

7. (7) Step 7. Apply risk weights.

   1. (a) The agency assigns each risk category and age/gender category a weight. The weight comes from either the model for clients who are age 17 and younger or from the model for clients age 18 and older.

   2. (b) In each model there are three types of weights.

      1. (i) Age/gender – Weights that correspond to the age/gender category of a client.
      2. (ii) CDPS – Weights that correspond to 58 of the CDPS risk categories.
      3. (iii) MRx – Weights that correspond to 45 of the MRx risk categories.

   3. (c) Table 5. Risk Score Weights

      Category Type	Category	Description	Weights for Children(age <18)	Weights for Adults(age 18+)
      Age/Gender	Age <1	Clients of age less than 1	0.91261	0.00000
      	Age 1 to 4	Clients age 1 to 4	0.31764	0.00000
      	Age 5 to 14, Male	Male clients age 5 to 14	0.25834	0.00000
      	Age 5 to 14, Female	Female clients age 5 to 14	0.26338	0.00000
      	Age 15 to 24, Male	Male clients age 15 to 24	0.25662	-0.01629
      	Age 15 to 24, Female	Female clients age 15 to 24	0.29685	0.03640
      	Age 25 to 44, Male	Male clients age 25 to 44	0.00000	0.04374
      	Age 25 to 44, Female	Female clients age 25 to 44	0.00000	0.06923
      	Age 45 to 64, Male	Male clients age 45 to 64	0.00000	0.13321
      	Age 45 to 64, Female	Female clients age 45 to 64	0.00000	0.06841
      	Age 65+	Clients age 65 and older	0.00000	-0.05623
      CDPS	CARVH	Cardiovascular, very high	0.84325	2.86702
      	CARM	Cardiovascular, medium	0.33428	0.73492
      	CARL	Cardiovascular, low	0.12835	0.24620
      	CAREL	Cardiovascular, extra low	0.04307	0.06225
      	PSYH	Psychiatric, high	0.40351	0.27085
      	PSYM	Psychiatric, medium	0.23892	0.00000
      	PSYML	Psychiatric, medium low	0.13796	0.00000
      	PSYL	Psychiatric, low	0.07675	0.00000
      	SKCM	Skeletal, medium	0.21071	0.42212
      	SKCL	Skeletal, low	0.08343	0.15467
      	SKCVL	Skeletal, very low	0.06244	0.06773
      	CNSH	Central Nervous System, high	0.80483	0.78090
      	CNSM	Central Nervous System, medium	0.31945	0.40886
      	CNSL	Central Nervous System, low	0.15106	0.18261
      	PULVH	Pulmonary, very high	1.14056	4.01723
      	PULH	Pulmonary, high	0.34356	0.39309
      	PULM	Pulmonary, medium	0.35587	0.31774
      	PULL	Pulmonary, low	0.11315	0.13017
      	GIH	Gastro, high	0.65934	1.34924
      	GIM	Gastro, medium	0.24699	0.24372
      	GIL	Gastro, low	0.09767	0.05104
      	DIA1H	Diabetes, type 1 high	0.27018	1.04302
      	DIA1M	Diabetes, type 1 medium	0.27018	0.23620
      	DIA2M	Diabetes, type 2 medium	0.13647	0.17581
      	DIA2L	Diabetes, type 2 low	0.13647	0.09635
      	SKNH	Skin, high	0.56322	0.37981
      	SKNL	Skin, low	0.23664	0.45155
      	SKNVL	Skin, very low	0.05697	0.02119
      	RENEH	Renal, extra high	1.80489	3.41999
      	RENVH	Renal, very high	0.59311	0.69251
      	RENM	Renal, medium	0.28630	0.92846
      	RENL	Renal, low	0.21048	0.17220
      	SUBL	Substance Abuse, low	0.15170	0.16104
      	SUBVL	Substance Abuse, very low	0.01794	0.08784
      	CANVH	Cancer, very high	1.19700	2.80074
      	CANH	Cancer, high	0.51985	0.97173
      	CANM	Cancer, medium	0.22164	0.38022
      	CANL	Cancer, low	0.10350	0.22625
      	DDM	Developmental Disability, medium	0.50073	0.27818
      	DDL	Developmental Disability, low	0.19696	0.05913
      	GENEL	Genital, extra low	0.00790	0.01121
      	METH	Metabolic, high	0.47167	0.47226
      	METM	Metabolic, medium	0.26297	0.11310
      	METVL	Metabolic, very low	0.11546	0.18678
      	PRGCMP	Pregnancy, complete	0.00244	0.00000
      	PRGINC	Pregnancy, incomplete	0.12631	0.51636
      	EYEL	Eye, low	0.09919	0.13271
      	EYEVL	Eye, very low	0.02835	0.00000
      	CERL	Cerebrovascular, low	0.14294	0.00000
      	AIDSH	AIDS, high	0.70597	0.47361
      	INFH	Infectious, high	0.70597	0.79689
      	HIVM	HIV, medium	0.26129	0.07937
      	INFM	Infectious, medium	0.26129	0.79689
      	INFL	Infectious, low	0.07784	0.05617
      	HEMEH	Hematological, extra high	5.37808	12.71981
      	HEMVH	Hematological, very high	0.72873	3.08836
      	HEMM	Hematological, medium	0.37824	0.63211
      	HEML	Hematological, low	0.18676	0.25601
      MRx	MRx1	Alcoholism	0.05982	0.01924
      	MRx2	Alzheimer's	0.00000	0.08112
      	MRx3	Anti-coagulants	0.34428	0.13523
      	MRx4	Asthma/COPD	0.08758	0.05751
      	MRx5	Attention Deficit	0.00000	0.00779
      	MRx6	Burns	0.16633	0.00000
      	MRx7	Cardiac	0.0906	0.06425
      	MRx8	Cystic Fibrosis	0.50399	0.37265
      	MRx9	Depression/Anxiety	0.06743	0.09436
      	MRx10	Diabetes	0.1519	0.17046
      	MRx11	EENT	0.00000	0.00072
      	MRx12	ESRD/Renal	1.24598	1.20707
      	MRx13	Folate Deficiency	0.17973	0.11899
      	MRx14	CMV Retinitis	0.37762	0.00000
      	MRx15	Gastric Acid Disorder	0.10082	0.15470
      	MRx16	Glaucoma	0.04221	0.12971
      	MRx17	Gout	0.00000	0.00000
      	MRx18	Growth Hormone	0.9741	1.59521
      	MRx19	Hemophilia/von Willebrands	13.56192	89.14461
      	MRx20	Hepatitis	0.03018	0.00000
      	MRx21	Herpes	0.0348	0.01725
      	MRx22	HIV	0.65537	1.01178
      	MRx23	Hyperlipidemia	0.00000	0.03791
      	MRx24	Infections, high	1.38405	1.51663
      	MRx25	Infections, medium	0.07462	0.06192
      	MRx26	Infections, low	0.00000	0.00918
      	MRx27	Inflammatory/Autoimmune	0.08075	0.20046
      	MRx28	Insomnia	0.07093	0.06437
      	MRx29	Iron Deficiency	0.13306	0.15054
      	MRx30	Irrigating Solution	0.87573	0.16387
      	MRx31	Liver Disease	0.45314	0.22681
      	MRx32	Malignancies	0.36859	0.44200
      	MRx33	Multiple Sclerosis/Paralysis	0.0345	0.04353
      	MRx34	Nausea	0.18219	0.17120
      	MRx35	Neurogenic Bladder	0.15282	0.07675
      	MRx36	Osteoporosis/Pagets	0.00000	0.00000
      	MRx37	Pain	0.0295	0.04151
      	MRx38	Parkinsons/Tremor	0.17163	0.06257
      	MRx39	Prenatal Care	0.00000	0.13192
      	MRx40	Psychotic Illness/Bipolar	0.22819	0.20274
      	MRx41	Replacement Solution	0.58622	1.49405
      	MRx42	Seizure Disorders	0.23997	0.19837
      	MRx43	Thyroid Disorder	0.03948	0.06326
      	MRx44	Transplant	0.37388	0.05810
      	MRx45	Tuberculosis	0.20006	0.00000

8. (8) Step 8. Sum risk weights to obtain the risk score.

   After obtaining the weights that correspond to a client's age/gender category and set of risk categories, the agency takes a sum of the values of all of the weights. This sum is the risk score for a client.

[Statutory Authority: RCW 41.05.021 and 41.05.160. WSR 22-17-166, § 182-557-0225, filed 8/24/22, effective 9/24/22; WSR 17-24-111, § 182-557-0225, filed 12/6/17, effective 1/6/18; WSR 15-17-065, § 182-557-0225, filed 8/14/15, effective 9/14/15.]