ICD10 Shihjui Lin Vikrant Deshmukh Katherine Sward Outline

ICD-10 Shih-jui Lin Vikrant Deshmukh Katherine Sward

Outline l Overview and History l Content of ICD-10 l Implementation l Examples l Modifications l Evaluation l Discussion

Requirements of an International Classification l l l l Comprehensive Well-defined Acceptable Attractive Reliable Conservative Compatible with: • • • previous classification of other sectors (e. g. social insurance) monitoring procedures (e. g. epidemiological reports)

Overview of ICD-10 l l l International Classification of Diseases and Related Health Problems, the 10 th Edition Maintained by the World Health Organization Classifies the causes of disease morbidity and mortality Contains diseases, symptoms, etiologies, and injuries Official Site: • http: //www. who. int/whosis/icd 10/

History of ICD l Origin (1893) l WHO (1946) l Revised every 10 years • International List of Causes of Death • International Statistical Institute (ISI) • Morbidity and mortality • ICD-10 (1994)

ICD Revisions Mortality ISI WHO Mortality Morbidity Revision Implementation in US 1 st 1900 -1909 2 nd 1910 -1920 3 rd 1921 -1929 4 th 1930 -1938 5 th 1939 -1948 6 th 1949 -1957 7 th 1958 -1967 8 th 1968 -1978 9 th 1979 -1998 10 th 1999 -present

Purpose of ICD-10 l WHO: • Statistically oriented classification system for • health census and statistics To permit the systematic analysis, interpretation and comparison of mortality and morbidity data collected in different countries or areas, at different times

Updates of ICD-10 l Must through a local Collaborating Centre • • • l E. g, US: National Center for Health Statistics (NCHS) Submit to WHO 3 to 6 months before Heads of Centres annual meeting Present in Heads of Centres meeting in October Updates: • • Publish no later than 15 months after each Centre Heads meeting Latest update available: 1999 (http: //www. who. int/whosis/icd 10/corr-eng. htm)

Content of ICD-10 l l l Volume 1: • • • Tabular List Cause-of-death titles and codes Classification at 3 - and 4 -character levels Volume 2: • • Instruction Manual Description, guidelines, and coding rules Volume 3: • • Alphabetical Index to diseases and nature of injury, external causes of injury Table of drugs and chemicals

ICD-10: The Code l l Core code: • • 3 character (1 letter + 2 digits) A 00 Up to 2, 600 categories Mandatory for reporting at the international level Extended code: • • the 4 th digit following a decimal point A 00. 0 Up to 26, 000 categories Recommended not required by WHO

ICD-10: The Classification l Two types of classification: • Main classification • diagnoses and health status • E 11 = Non-insulin dependent diabetes mellitus • Supplementary classification • generally outside the formal diagnoses but related to health care • Z 83. 3 = Family history of diabetes mellitus

ICD-10 Hierarchy for Classification l l 9, 275 codes used in US • ftp: //ftp. cdc. gov/pub/Health_Statistics/NCHS/Publications/ICD 10/ 3 level hierarchy • Level 1: the 21 chapters • 21 categories • Level 2: the 1 st – 3 rd characters (A 00) • 1643 categories • Level 3: the 1 st – 4 th characters (A 00. 0) • 7611 categories l Site for browsing the hierarchy and searching diseases: • http: //www. med-ia. ch/bolinosmed/codifications/icd 10/

Example: ICD-10 Hierarchy Level 1 l Level 2 Chap. IV Endocrine, nutritional and metabolic diseases (E 00 -E 90) • Level 3 • • l l E 11 = Type 2 diabetes mellitus • • E 11. 1 = with ketoacidosis E 11. 2 = with renal complications E 11. 3 = with ophthalmic complications … E 12 = Malnutrition-related diabetes mellitus … Chap. V Mental and behavioral disorders (F 00 -F 99) …

The 21 Chapters (1/3) • • • I Certain infectious and parasitic diseases (A 00 -B 99) II Neoplasms (C 00 -D 48) III Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D 50 -D 89) IV Endocrine, nutritional and metabolic diseases (E 00 -E 90) V Mental and behavioral disorders (F 00 -F 99) VI Diseases of the nervous system (G 00 -G 99) VII Diseases of the eye and adnexa (H 00 -H 59) VIII Diseases of the ear and mastoid process (H 60 -H 95) IX Diseases of the circulatory system (I 00 -I 99) X Diseases of the respiratory system (J 00 -J 99)

The 21 Chapters (2/3) • • XI Diseases of the digestive system (K 00 -K 93) XII Diseases of the skin and subcutaneous tissue (L 00 L 99) XII Diseases of the musculoskeletal system and connective tissue (M 00 -M 99) XIV Diseases of the genitourinary system (N 00 -N 99) XV Pregnancy, childbirth and the puerperium (O 00 -O 99) XVI Certain conditions originating in the perinatal period (P 00 -P 96) XVII Congenital malformations, deformations and chromosomal abnormalities (Q 00 -Q 99) XVIII Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R 00 -R 99) • R 42 = Dizziness and giddiness

The 21 Chapters (3/3) • • • l XIX Injury, poisoning and certain other consequences of external causes (S 00 -T 98) • S 21 = Open wound of thorax XX External causes of morbidity and mortality (V 01 -Y 98) • W 54. 0 = Bitten by dog • V 47 = Car occupant injured in collision with fixed or stationary object XXI Factors influencing health status and contact with health services (Z 00 -Z 99) • Z 83. 3 = Family history of diabetes mellitus U is not used (reserved for future updates)

Most Important Coding Rules of ICD-10 1— Highest Level of Specificity 2— Daggers (†) and asterisks (*) are coded together, daggers first 3— Principal disease: one disease of major medical cost

1. Highest Level of Specificity l As specific as possible • Patient: • Type 2 diabetes mellitus with renal complications • Code: • E 11. 2 = Type 2 diabetes mellitus with renal complications • Not E 11 = Type 2 diabetes mellitus

2. Dagger and Asterisk l l For a disease encoded by two codes • • Dagger represents etiological aspects. Asterisk refers to anatomical location Example: • For Renal tuberculosis: A 18. 1† urogenital tuberculosis N 29. 1* infectious disease of kidney and ureter classified elsewhere. .

More on N 29 l N 29 Other disorders of kidney and ureter in diseases classified elsewhere • Code first underlying disease, such as: • Excludes: disorders of kidney and ureter in: • amyloidosis (E 85) • nephrocalcinosis (E 83. 5) • schistosomiasis (B 65. 0 -B 65. 9) • cystinosis (E 72. 0)

3. Principal disease l Only one principal disease allowed l The main reason for medical service If more than one diseases fulfill criteria, choose the disease with the largest amount of medical cost l

Implementation l l Developed by WHO Modified & distributed in different countries by the respective health agencies. Differences in the implementation permissible Reporting must be done strictly in ICD-10

Role of WHO l l l Conduct the process of periodic revisions Lead the updating between revisions Develop new methodologies for classifying and analyzing data Facilitate training on ICD, its family and its framework among member countries Facilitate the improvement of the basic data

Usage in Current Systems l Intended use l Actual use • Morbidity & Mortality reporting • Billing & Financial • Quality Assurance • Administrative Planning • Epidemiological & other Research

Licensing & Costs (from WHO) l l ICD-10 Volume 1: Tabular List at Sw. fr. 130. -/US $117. 00 ICD-10 Volume 2: Instruction Manual at Sw. fr. 40. -/US $36. 00 ICD-10, Volume 3: Alphabetical Index at Sw. fr. 130. -/US $117. 00 WHO retains copyright

Licensing & Costs (U. S. ) l Official version can be purchased from WHO • WHO Publications Center USA • • • 49 Sheridan Avenue Albany, NY 12210 Same costs at from WHO ($540. 00 for the set) List of causes for mortality data are available from the NCHS web site ftp: //ftp. cdc. gov/pub/Health_Statistics/NCHS/ Publications/ICD 10/ Other tabulation lists can be found in Instruction Manual Part 9 at www. cdc. gov/nchs/about/major/dvs/im. htm

ICD-10 Languages Available (WHO editions) English Basque German Latvian Slovak French Croatian Greek Lithuanian Slovene Arabic Czech Hungarian Mongolian Swedish Chinese Danish Icelandic Norwegian Thai Russian Dutch Italian Polish Turkish Spanish Estonian Japanese Portuguese Ukrainian Armenian Finnish Korean Serbian Uzbek http: //www. who. int/whosis/icd 10/language. htm

Implementation Criteria l Full implementation of ICD-10: A country is considered as having fully implemented ICD‑ 10 if it is currently used for: • • l Mortality: Causes of death in death certificates are coded using original ICD‑ 10 codes Morbidity: Diagnoses in all (or at least in the majority) hospitals are coded in ICD‑ 10 The fact that a country is reporting to WHO mortality data coded in ICD-10, and has the ability to produce tabulations of hospital discharge data by ICD-10 codes, can serve as a simple criterion or evidence of ICD-10 implementation in a given country

Implementation Criteria l l Partial implementation for morbidity: • The use of ICD‑ 10 is limited to selected hospitals or administrative/geographical areas. Preparatory phase: • • • A firm decision and action taken by national health administrations to start preparations for using ICD‑ 10; Translation of ICD‑ 10 manuals into national language or other national adaptations, if applicable; acquisition of sufficient number of copies of ICD‑ 10 manuals and other related materials; Adaptation of data registration instruments to ICD‑ 10; training of coders and other health professionals; pilot testing in selected health establishments.

ICD-10 Implementation Time-frames http: //www. who. int/whosis/icd 10/implemen. htm

Summary of ICD-10 implementation status September 2002 WHO Region (No of countries/territories) No of countries reported full implementation for mortality Full implementation for mortality & morbidity Comments AFRO (46) 16 (35%) 14 (30%) Actual level of implementation is likely to be much lower, as the data for 13 of the countries are from the 2001 survey and without details. AMRO (49) 46 (93%) 32 (70%) EMRO (23) 6 (26%) 4 (17%) Seven countries (30%) reported partial implementation for mortality and/or morbidity EURO (51) 42 (82%) 33 (65%) Four countries will start using ICD-10 for mortality from 1 st January 2003, increasing the implementation for mortality up to 90%. SEARO (10) 8 (80%) ? Information on mortality coding as per November 2000. No survey in 2002. WPRO (37) 20 (54%) 16 (43%) Partial implementation reported for China, Philippines, Viet Nam, i. e. full implementation expected in coming years. Actual level of implementation in the Region may be lower, as the data for some countries are from previous surveys and without details. Total (216) 138 (64%) 99 (46%) Prokhorskas et al WHO/GPE/CAS/C/02. 17

Differences between ICD-10 and National / Specialist Classification

Automatic conversion from ICD-10 to ICD-9 l l Unambiguous mapping: 87% Mapping based on selection table: 9% Compromise between preserving information content & local integrity: 2. 4% Impossible to match automatically: 1. 6% Schulz S et al (1998) Meth Inform Med 37: 254 -9

Automatic conversion from ICD-9 to ICD-10 l l Unambiguous mapping: 64% Codes have been reclassified Some Codes no longer exist Others do not have equivalents in ICD 10 Schulz S et al (1998) Meth Inform Med 37: 254 -9

Differences between ICD-9 & ICD-10 : Breast Cancer l l l l 174 malig neo female breast 1740 malig neo nipple 1741 mal neo breast-central 1742 mal neo breast up-inner 1743 mal neo breast low-inner 1744 mal neo breast up-outer 1745 mal neo breast low-outer 1746 mal neo breast-axillary 1748 malign neopl breast nec 1749 malign neopl breast nos 175 malig neo male breast 1750 mal neo male nipple 1759 mal neo male breast nec l l l l l C 50 malignant neoplasm of breast C 50. 0 nipple and areola C 50. 1 central portion of breast C 50. 2 upper-inner quadrant of breast C 50. 3 lower-inner quadrant of breast C 50. 4 upper-outer quadrant of breast C 50. 5 lower-outer quadrant of breast C 50. 6 axillary tail of breast C 50. 8 overlapping lesion of breast C 50. 9 breast, unspecified

Differences between ICD-9 & ICD-10 : Cerebral Embolism l 4340 cerebral thrombosis 43400 cerbral thromb w/o cva 43401 cerbral thromb w/cva l l l l cerebral artery occlusion 4341 cerebral embolism 43410 cerbebral embol w/o cva 43411 cerebral embolsm w/cva 4349 cerebr artery occlus nos 43490 cerbrl art occ w/o infar 43491 cerbrl art occlus w/cva l l l l l I 63. 0 cerebral infarction due to thrombosis of precerebral arteries I 63. 1 cerebral infarction due to embolism of precerebral arteries I 63. 2 cerebral infarction due to unspecified occlusion or stenosis of precerebral arteries I 63. 3 cerebral infarction due to thrombosis of cerebral arteries I 63. 4 cerebral infarction due to embolism of cerebral arteries I 63. 5 cerebral infarction due to unspecified occlusion or stenosis of cerebral arteries I 63. 6 cerebral infarction due to cerebral venous thrombosis, nonpyogenic I 63. 8 other cerebral infarction I 63. 9 cerebral infarction, unspecified

ICD-9 to ICD-10 comparison l Comparability ratio = ICD-10/ICD-9 l Cerebrovascular diseases example • • • The comparability ratio for Cerebrovascular diseases is 1. 0588, which indicates a net increase of about 6 percent in allocation to Cerebrovascular diseases with the implementation of ICD– 10. Most of the deaths added to Cerebrovascular diseases in ICD– 10 were classified as pneumonia in ICD– 9. This increase is due primarily to the change in Rule 3 (Because pneumonia is a direct consequence of Cerebrovascular diseases, Cerebrovascular diseases are selected instead of pneumonia as the underlying cause of death in ICD– 10 when both are listed on the death certificate) http: //www. cdc. gov/nchs/data/nvsr 49/nvsr 49_02. pdf

Modification of ICD-10 l l l A set of extended codes • • • Developed by different countries/organizations Using 5 th and 6 th digits Sub-categories under the ICD-10 3 -level hierarchy (Level 4) Codes are • • Consistent in 1 st – 4 th characters (ICD-10) Different in 5 th – 6 th digits (extension) Examples: • • • AM: Australian modification CA: Canadian enhancement CM: clinical modification

ICD-10 Modification Hierarchy l E 00 -E 90 = Endocrine, nutritional and metabolic diseases • • • l l E 11 = Type 2 diabetes mellitus • E 11. 2 = Type 2 diabetes mellitus with renal complications 2 diabetes mellitus with • • E 11. 3 = Type 2 diabetes mellitus with ophthalmic complications … other diabetic renal complication E 12 = Malnutrition-related diabetes mellitus … F 00 -F 99 = Mental and behavioural disorders …

ICD-10 Modification Hierarchy WHO Standard l E 00 -E 90 = Endocrine, nutritional and metabolic diseases • E 11 = Type 2 diabetes mellitus • E 11. 2 = Type 2 diabetes mellitus with renal complications • E 11. 21 • Type 2 diabetes mellitus with diabetic nephropathy • Type 2 diabetes mellitus with intercapillary glomerulosclerosis Modification • Type 2 diabetes mellitus with intracapillary glomerulonephrosis • Type 2 diabetes mellitus with Kimmelstiel-Wilson disease • …. . • E 11. 29 • Type 2 diabetes mellitus with other diabetic renal complication • • l l • • E 11. 3 = Type 2 diabetes mellitus with ophthalmic complications … E 12 = Malnutrition-related diabetes mellitus … F 00 -F 99 = Mental and behavioural disorders …

Codes of Modification l Different meaning in different modifications: • ICD-10: • CM: • • E 11. 2 = Type 2 diabetes mellitus with renal complications • E 11. 22 = • • Type 2 diabetes mellitus with Ebstein's disease Type 2 diabetes mellitus with renal tubular degeneration AM: • E 11. 22 = • Type 2 diabetes mellitus with established diabetic nephropathy

ICD-10 -AM l l l AM = Australian Modification National Centre for Classification in Health, Australia Coding Standards in • • Australia New Zealand Fourth Edition • • Will be released in February 2004 Will be Implement Ted in July 2004 Official site: • http: //www 2. fhs. usyd. edu. au/ncch/

ICD-10 -CA l l l The Canadian Enhancement Canadian Institute for Health Information Standard in Canada • • for morbidity classification replaces ICD-9 and ICD-9 -CM Started the implementation in 2001 Official site: • http: //secure. cihi. ca/cihiweb/disp. Page. jsp? cw_page=codingclass_icd 10_e

ICD-10 -CM l l l Clinical Modification National Center for Health Statistics (NCHS) Final draft (Jun. 2003) 2 year implementation Not yet an anticipated implementation date Official Site: • http: //www. cdc. gov/nchs/about/otheract/icd 9/abticd 10. htm

Purpose of ICD-10 -CM l l l To expand distinctions for ambulatory and managed care encounters To include new concepts • • diseases medical knowledge To incorporate changes made to ICD-9 -CM since ICD-10 implementation

Purpose of ICD-10 -CM l To harmonize with other classification standards • • ICD-O-2 • • • Used by cancer registry programs since 1995 Chapter 2 (Neoplasms) and morphology codes correspond to ICD-O-2 http: //seer. cancer. gov/tools/conversion/ NANDA • • • Nursing classification Harmonization (90 -95%) with NANDA http: //www. nanda. org/

Development of ICD-10 -CM l Three phases of development • • • l Prototype developed under contract 20 Technical Advisory Panel members Enhancements by NCHS, providers & other users Further enhancements based on public comments • • Review period: 12/1997 – 02/1998 Draft on the website Over 1, 200 comments 22 organizations/individuals Final draft (Jun. 2003)

Content of ICD-10 -CM (Draft) l l 23, 122 codes (http: //www. ahima. org/dc/NCVHSreport 092303. ppt) 5 th and 6 th digits More specific diseases, symptoms, injuries and other information related to health care Example: • • ICD-10: • E 11. 2 Type 2 diabetes mellitus with renal complications ICD-10 -CM: • • • E 11. 21 • with diabetic nephropathy • with intercapillary glomerulosclerosis • with intracapillary glomerulonephrosis • with Kimmelstiel-Wilson disease… … E 11. 29 • with other diabetic renal complication

Summary of ICD-10&CM ICD-10 -CM Purpose International standard of morbidity and mortality classification Greater specificity Extended concepts Organization WHO NCHS, US Content 21 chapters: diseases, symptoms, conditions, etc. Elaborate subcategories extended from ICD-10 Code format E 11. 22 x Size/maximal 9, 275 / 26, 000 23, 122 / 2, 600, 000 Status in U. S. Mortality (1999) Morbidity (2000) Draft (2003) not implemented

Evaluation l l l What ICD is Desiderata Other strengths/weaknesses

What ICD-10 is l l A classification (arrangement of terms into groups based on their essential characteristics: chapters). A terminology (list of terms within a domain). A thesaurus: has an alphabetical index. (And a nomenclature? : very limited, in an appendix, to specify the morphology of neoplasms).

Content +/- There is a formal process to add content; significant increase in amount of content since ICD-9 There is not a formal method for recognizing and filling in gaps (classifications are based on importance in public health, frequency of occurrence…) Revisions every decade may not capture rapid growth in medical knowledge

Concept Orientation +/- Grouped in a way that was felt to be most suitable for general epidemiology and health care evaluation Inconsistent decisions (theoretical compromises between classifying based on etiology, anatomical site, onset circumstances, etc) Categorizations can be confusing, especially for lay coders. (Is Gastric Cancer in the GI diseases or the neoplasms? )

Concept permanence Some terms have been deleted Some conditions have been re-categorized (e. g. hemorrhage)

Nonsemantic Identifiers Codes are hierarchical Codes are fixed-length alphanumeric -

Polyhierarchy - Most things have only one place in the hierarchy There a few exceptions (the dagger/asterisk codes)

Formal definitions - A small amount of definitions and synonyms in the appendices No formal “is_a” relationships

The Infamous NEC and NOS l NEC (“other”): • when information at hand specifies a condition but • l no separate code for that condition is provided E 13 = other specified diabetes mellitus NOS (“unspecified”): • when information at hand does not permit either a more specific or “other” code assignment l l • E 14= unspecified diabetes mellitus Subcategories. 8 (“other xxx”) and. 9 (“xxx unspecified”) are not consistent throughout “Practically never occurs that a disease cannot be assigned an ICD code. ”

Multiple Granularities + Three character codes mandatory level Four character code optional but recommended Different countries have different need for detail ICD-10 -CM goes to a 5 th character for more detail (U. S. coding rules say use the longest code available)

Multiple consistent views +/Single hierarchy, can expand (4 -5 digit code) or collapse (3 digit code) Users may adapt to some extent, encouraged to coordinate adaptations through WHO

Representing Context - The only relationships are within the strict hierarchy (no “grammar” and no defined relationships between concepts) Little if any context (“how it will be used”) A few diseases have alternate codes Intent is not to combine concepts to create new codes

Graceful Evolution - Code changes, re-use of codes, change categories You need to know which version of ICD you’re using to determine the meaning of a code

Recognizing Redundancy Most conditions appear only one place in the hierarchy + Except for the dagger/asterisk conditions! -

General Weakness l ICD is a classification. 4 -digit categories usually represent sets of diseases rather than single diseases l No official ICD definitions for the meanings of categories: the ‘semantic content’ of a category can only be estimated

Estimating ‘Semantic Content’ l l 1—the name of the category (e. g. J 67 Hypersensitivity pneumonitis due to organic dust) 2—officially listed inclusions and exclusions (e. g. K 14. 0 glossitis Excludes K 14. 4 atrophic glossitis)

Estimating ‘Semantic Content’ l 3—The place of the entry in the structure of the system (e. g. D 02. 2 and D 14. 3 both are bronchus and lung. However, D 02. 2 falls under D 02 which is carcinoma in situ of the respiratory system and middle ear and D 14. 3 belongs to D 14 which is benign neoplasm of the respiratory system and middle ear. )

Weaknesses Requires human coders (often non. MDs l Code ‘probable’ diseases as established diagnosis l Requires large code book and instruction manual if software is not available l

Weaknesses Continued l l Inter-rater reliability questionable For diseases surveillance, ICD revisions may create erroneous spikes or valleys NEC and NOS used quite often Not enough codes (categories too broad)?

Issues - practical l l Changes not updated on WHO website for dissemination Not all countries aware of updates to rules, terms and classes Countries using different versions of ICD 10 - problems particularly for mortality Opportunities for electronic distribution Source: Proceedings of ICD 10 Update Reference Committee

Issues - clinical l l Some areas in urgent need of major clinical revision, e. g. diabetes Some areas being revised by WHO outside URC process (Mental Health) Compatibility with FIC (ICD-O, ICF, ICE-CI) Changes from clinical modifications Need for a procedure classification Source: Proceedings of ICD 10 Update Reference Committee

Strengths l l Ubiquitous "the most common disease classification system in routine use" l l (Schulz et al. , 1998, p. 254) International usage; collaboration between multiple countries, organizations, agencies. Revisions by international collaborative group.

Strengths l l l Works well for its intended purpose (population statistics, mortality comparisons, statistical study of disease phenomena) Less effective but still sometimes useful for other purposes (lists of diagnoses, reason for admission, reason for consultation) IF these codes will be used as statistical aggregates Insufficient detail for some purposes (clinical decision making)

Requirements of an International Classification l l l l Comprehensive Well-defined Acceptable Attractive Reliable Conservative Compatible with: • • • previous classification of other sectors (e. g. social insurance) monitoring procedures (e. g. epidemiological reports)

References l l l Chute CG, Cohn SP, Campbell KE, Oliver DE, Campbell JR. The content coverage of clinical classifications. For The Computer-Based Patient Record Institute's Work Group on Codes &Structures. J Am Med Inform Assoc. 1996 May. Jun; 3(3): 224 -33. de. Keizer, N. F. , Abu-Hanna, A. , Zwetsloot-Schonk, J. H. M. . Understanding terminological systems I: Terminology & Typology. Methods of Information in Medicine. 2000. 39, 16 -21. Gersenovic M. , The ICD Family of Classifications Meth Inform Med 1995; 34: 172 -5 ICD-10 vol. 1, 2, 3 World Health Organization Geneva, Switzerland. 1992 Schulz S, Zaiss A, Brunner R, Spinner D, Klar R. Conversion Problems concerning Automated Mapping from ICD-10 to ICD 9. Meth Inform Med 1998; 37: 254 -9

References l World Health Organization (WHO) http: //www. who. int l WHO statistical information http: //www. who. int/whosis/icd 10/ l Centers for Disease Control (CDC) National Center for Health Statistics (NCHS) l l http: //www. cdc. gov/nchs/about/otheract/icd 9/abticd 10. htm http: //www. cdc. gov/nchs/about/major/dvs/icd 10 des. htm l http: //www. cms. hhs. gov/medlearn/icd 9 code. asp l