ICD-10 General Equivalence Mappings (GEMs) 

ICD-9-CM Coordination & Maintenance Committee
March 11, 2009
Why Do We Need the GEMs?
I-9 and I-10 are different languages
• Codes are the language of healthcare
• As with Spanish and English, ICD-9 and ICD-10 are different languages 
– 30-year generation gap between ICD-9-CM and ICD-10-CM
– ICD-10 reflects the current understanding and practice of medicine

Why Do We Need the GEMs?
Because Different is Good
• If the differences were not significant, there would be no incentive to change
65100 Twin pregnancy, unspecified as to episode of care 
 	From and to  O30009 Twin pregnancy, unspecified, unspecified trimester  
 	From  O30019 Twin pregnancy, monoamniotic/monochorionic, unspecified trimester  
 	From  O30099 Other twin pregnancy, unspecified trimester  
 
65101 Twin pregnancy, delivered 
 	To  O30009 Twin pregnancy, unspecified, unspecified trimester  
 
65103 Twin pregnancy, antepartum condition or complication 
 From and to  O30001 Twin pregnancy, unspecified, first trimester  
 From and to  O30002 Twin pregnancy, unspecified, second trimester  
 From and to  O30003 Twin pregnancy, unspecified, third trimester  
 From  O30011 Twin pregnancy, monoamniotic/monochorionic, first trimester  
 From  O30012 Twin pregnancy, monoamniotic/monochorionic, second trimester  
 From  O30013 Twin pregnancy, monoamniotic/monochorionic, third trimester  
 From  O30091 Other twin pregnancy, first trimester  
 From  O30092 Other twin pregnancy, second trimester  
 From  O30093 Other twin pregnancy, third trimester 

Why Do We Need the GEMs?
As a general translation aid
• The GEMs are a general purpose ICD-9/ICD-10 translation dictionary
– Facilitate translation from ICD-9 to ICD-10
– Facilitate translation from ICD-10 to ICD-9
82002 Fracture of midcervical section of femur, closed 

 From  S72031A Displaced midcervical fracture of right femur, initial encounter for closed fracture  
 From  S72031G Displaced midcervical fracture of right femur, subsequent encounter for closed fracture with delayed healing  
 From  S72032A Displaced midcervical fracture of left femur, initial encounter for closed fracture  
 From  S72032G Displaced midcervical fracture of left femur, subsequent encounter for closed fracture with delayed healing  
 From and to  S72033A Displaced midcervical fracture of unspecified femur, initial encounter for closed fracture  
 From  S72033G Displaced midcervical fracture of unspecified femur, subsequent encounter for closed fracture with delayed healing  
 From  S72034A Nondisplaced midcervical fracture of right femur, initial encounter for closed fracture  
 From  S72034G Nondisplaced midcervical fracture of right femur, subsequent encounter for closed fracture with delayed healing  
 From  S72035A Nondisplaced midcervical fracture of left femur, initial encounter for closed fracture  
 From  S72035G Nondisplaced midcervical fracture of left femur, subsequent encounter for closed fracture with delayed healing  
 From and to  S72036A Nondisplaced midcervical fracture of unspecified femur, initial encounter for closed fracture  
 From  S72036G Nondisplaced midcervical fracture of unspecified femur, subsequent encounter for closed fracture with delayed healing   

Why Do We Need the GEMs?
I-10 is much more specific
• Pertinent clinical detail has been added to ICD-10 
82002 Fracture of midcervical section of femur, closed 

 From  S72031A Displaced midcervical fracture of right femur, initial encounter for closed fracture  
 From  S72031G Displaced midcervical fracture of right femur, subsequent encounter for closed fracture with delayed healing  
 From  S72032A Displaced midcervical fracture of left femur, initial encounter for closed fracture  
 From  S72032G Displaced midcervical fracture of left femur, subsequent encounter for closed fracture with delayed healing  
 From  S72033A Displaced midcervical fracture of unspecified femur, initial encounter for closed fracture  
 From  S72033G Displaced midcervical fracture of unspecified femur, subsequent encounter for closed fracture with delayed healing  
 From  S72034A Nondisplaced midcervical fracture of right femur, initial encounter for closed fracture  
 From  S72034G Nondisplaced midcervical fracture of right femur, subsequent encounter for closed fracture with delayed healing  
 From  S72035A Nondisplaced midcervical fracture of left femur, initial encounter for closed fracture  
 From  S72035G Nondisplaced midcervical fracture of left femur, subsequent encounter for closed fracture with delayed healing  
 From  S72036A Nondisplaced midcervical fracture of unspecified femur, initial encounter for closed fracture  
 From  S72036G Nondisplaced midcervical fracture of unspecified femur, subsequent encounter for closed fracture with delayed healing  

Why Do We Need the GEMs?
For I-9 verbiage not in I-10
• Some distinctions in I-9 have been eliminated

A5483 Gonococcal heart infection 
Alternate terms 
 Gonococcal endocarditis
 Gonococcal myocarditis
 Gonococcal pericarditis
 
 	To  09883 Gonococcal pericarditis  
	To  09884 Gonococcal endocarditis  
 	To  09885 Other gonococcal heart disease 

Why Do We Need the GEMs?
There are new I-10 categories
• I-10 captures types of information not available anywhere in I-9
T500x6A Underdosing of mineralocorticoids and their antagonists, initial encounter 
T501x6A Underdosing of loop [high-ceiling] diuretics, initial encounter 
T502x6A Underdosing of carbonic-anhydrase inhibitors, benzothiadiazides and other diuretics, initial encounter 
T503x6A Underdosing of electrolytic, caloric and water-balance agents, initial encounter 
T504x6A Underdosing of drugs affecting uric acid metabolism, initial encounter 
T505x6A Underdosing of appetite depressants, initial encounter 
T506x6A Underdosing of antidotes and chelating agents, initial encounter 
T507x6A Underdosing of analeptics and opioid receptor antagonists, initial encounter 
T508x6A Underdosing of diagnostic agents, initial encounter 
T50906A Underdosing of unspecified drugs, medicaments and biological substances, initial encounter 
T50996A Underdosing of other drugs, medicaments and biological substances, initial encounter 
T50A16A Underdosing of pertussis vaccine, including combinations with a pertussis component, initial encounter 
T50A26A Underdosing of mixed bacterial vaccines without a pertussis component, initial encounter 
T50A96A Underdosing of other bacterial vaccines, initial encounter 
T50B16A Underdosing of smallpox vaccines, initial encounter 
T50B96A Underdosing of other viral vaccines, initial encounter 
T50Z16A Underdosing of immunoglobulin, initial encounter 
T50Z96A Underdosing of other vaccines and biological substances, initial encounter

Why Do We Need the GEMs?
Translation can be tricky
• Some concepts expressed by one I-10 code need more than one I-9 code for a complete translation
0270346 Dilation of Coronary Artery, One Site, Bifurcation, with Drug-eluting Intraluminal Device, Percutaneous Approach 
 To  I9 cluster  
   0066 Percutaneous transluminal coronary angioplasty [PTCA] or coronary atherectomy  
 0040 Procedure on single vessel  
 0045 Insertion of one vascular stent  
 3607 Insertion Of Drug-Eluting Coronary Artery Stents(S)  
 0044 Procedure on vessel bifurcation  
 
 
027034Z Dilation of Coronary Artery, One Site with Drug-eluting Intraluminal Device, Percutaneous Approach 
 To  I9 cluster  
   0066 Percutaneous transluminal coronary angioplasty [PTCA] or coronary atherectomy  
 0040 Procedure on single vessel  
 0045 Insertion of one vascular stent  
 3607 Insertion Of Drug-Eluting Coronary Artery Stents(S)

What are the GEMs?
Translation reference
• A bi-directional code translation dictionary between ICD-9-CM and ICD-10
E1021 Type 1 diabetes mellitus with diabetic nephropathy 
 From  25043 Diabetes with renal manifestations, type I [juvenile type], uncontrolled  
 To  I9 cluster  
   25041 Diabetes with renal manifestations, type I [juvenile type], not stated as uncontrolled  
 58381 Nephritis and nephropathy, not specified as acute or chronic, in diseases classified elsewhere  
 
 
E1022 Type 1 diabetes mellitus with diabetic chronic kidney disease 
 To  25041 Diabetes with renal manifestations, type I [juvenile type], not stated as uncontrolled  
 
E1029 Type 1 diabetes mellitus with other diabetic kidney complication 
 From and to  25041 Diabetes with renal manifestations, type I [juvenile type], not stated as uncontrolled  

What are the GEMs composed of?
 Alternatives
• The GEMs give all plausible translation alternatives for the complete meaning of the code being looked up (source system code)
– Tabular instruction, index entries, guidelines, and applicable Coding Clinic advice

What are the GEMs composed of?
 Alternatives
• When there is only one alternative in a GEM, we can say we have a “one-to-one” translation
– Does not necessarily mean the codes are identical
S72031A Displaced midcervical fracture of right femur, initial encounter for closed fracture 
 To  82002 Fracture of midcervical section of femur, closed  

What are the GEMs composed of? 
 Alternatives continued
• There may be multiple translation alternatives for a source system code, all of which are equally plausible
– The complete meaning of ‘Burn’ in I-9 includes both:
• thermal burns (translates to ‘Burn’ in I-10) 
• chemical burns (translates to ‘Corrosion’ in I-10)

94223 Blisters with epidermal loss due to burn (second degree) of abdominal wall 
 
 From and to  T2122xA Burn of second degree of abdominal wall, initial encounter  
 From and to  T2122xD Burn of second degree of abdominal wall, subsequent encounter  
 From and to  T2162xA Corrosion of second degree of abdominal wall, initial encounter  
 From and to  T2162xD Corrosion of second degree of abdominal wall, subsequent encounter 

What are the GEMs composed of? 
I-9 Clusters
• I-9 cluster: more than one I-9 code is required to equal a complete translation of one I-10 code
E11341 Type 2 diabetes mellitus with severe nonproliferative diabetic retinopathy with macular edema 
 To  I9 cluster  
   25050 Diabetes with ophthalmic manifestations, type II or unspecified type, not stated as uncontrolled  
 36206 Severe nonproliferative diabetic retinopathy  
 36207 Diabetic macular edema 

What are the GEMs composed of? 
I-10 Clusters
• I-10 cluster: more than one I-10 code is required to equal a complete translation of one I-9 code
4862 Anterior Resection Of Rectum With Synchronous Colostomy 
 To  I10 cluster  
   	0DTP0ZZ Resection of Rectum, Open Approach 
 or 0DTP4ZZ Resection of Rectum, Percutaneous Endoscopic Approach 
 or 0DTP7ZZ Resection of Rectum, Via Natural or Artificial Opening 
 or 0DTP8ZZ Resection of Rectum, Via Natural or Artificial Opening Endoscopic  
 AND
 or	0D1N0Z4 Bypass Sigmoid Colon to Cutaneous, Open Approach 
 or 0D1N4Z4 Bypass Sigmoid Colon to Cutaneous, Percutaneous Endoscopic Approach 
 or 0D1N8Z4 Bypass Sigmoid Colon to Cutaneous, Via Natural or Artificial Opening Endoscopic 

What are the GEMs composed of? 
ICD-9-CM to ICD-10-CM detail
• Source system code 414.01
– Translation includes the complete meaning of the source system code
– Translates to a single comparably specific alternative in the ICD-9-CM to ICD-10-CM GEM
41401 Coronary atherosclerosis of native coronary artery 
 To  I2510 Atherosclerotic heart disease of native coronary artery without angina pectoris  

What are the GEMs composed of? 
ICD-10-CM to ICD-9-CM detail
• Source system code I25.110 contains both underlying cause and acute exacerbation
– Target system code 414.01 is part of an I-9 cluster in the ICD-10-CM to ICD-9-CM GEM
I25110 Atherosclerotic heart disease of native coronary artery with unstable angina pectoris 
 To  I9 cluster  
   41401 Coronary atherosclerosis of native coronary artery  
 	4111 Intermediate coronary syndrome

What are the GEMs composed of? 
ICD-9-CM to ICD-10-PCS detail
• Source system code 86.59
– Because I-9 does not specify the anatomic site, all PCS body parts are plausible translation alternatives
8659 Suture Of Skin And Subcutaneous Tissue Of Other Sites 
 To  0JQ10ZZ Repair Face Subcutaneous Tissue and Fascia, Open Approach  
 To  0JQ13ZZ Repair Face Subcutaneous Tissue and Fascia, Percutaneous Approach  
 To  0JQ40ZZ Repair Anterior Neck Subcutaneous Tissue and Fascia, Open Approach  
 To  0JQ43ZZ Repair Anterior Neck Subcutaneous Tissue and Fascia, Percutaneous Approach  
 To  0JQ50ZZ Repair Posterior Neck Subcutaneous Tissue and Fascia, Open Approach  
 To  0JQ53ZZ Repair Posterior Neck Subcutaneous Tissue and Fascia, Percutaneous Approach  
 To  0JQ60ZZ Repair Chest Subcutaneous Tissue and Fascia, Open Approach  
 To  0JQ63ZZ Repair Chest Subcutaneous Tissue and Fascia, Percutaneous Approach  
 To  0JQ70ZZ Repair Back Subcutaneous Tissue and Fascia, Open Approach  
 To  0JQ73ZZ Repair Back Subcutaneous Tissue and Fascia, Percutaneous Approach  
 To  0JQ80ZZ Repair Abdomen Subcutaneous Tissue and Fascia, Open Approach  
 To  0JQ83ZZ Repair Abdomen Subcutaneous Tissue and Fascia, Percutaneous Approach

What are the GEMs composed of? 
ICD-10-PCS to ICD-9-CM detail
• Source system code 0JQ60ZZ
– The more precise PCS code specifies body part and approach
–  Several non-specific I-9 codes are plausible translation alternatives for the PCS root operation Repair
0JQ60ZZ Repair Chest Subcutaneous Tissue and Fascia, Open Approach 
 To  8365 Other Suture Of Muscle Or Fascia  
 To  8389 Other Plastic Operations On Fascia  
 To  8659 Suture Of Skin And Subcutaneous Tissue Of Other Sites 

How do I read the GEMs?
GEM file format
• Source system code on the left side
• Target system code in the middle
• Flags on the right
T500x1A 	9620  		10111
T500x1A 	E8580 	10112
T500x1D 	9620  		10111
T500x1D 	E8580 	10112
T500x1S 	9090  		10111
T500x1S 	E9292 	10112
T500x2A 	9620  		10111
T500x2A 	E9504 	10112
T500x2D 	9620  		10111
T500x2D 	E9504 	10112
T500x2S 	9090  		10111
T500x2S 	E959  		10112

How do I read the GEMs?
Adding code descriptions
• Import GEM files to a spreadsheet or database, and add code descriptions for readability
T500x1A Poisoning by mineralocorticoids and their antagonists, accidental (unintentional), initial encounter 
 To  I9 cluster  
   9620 Poisoning by adrenal cortical steroids  
 E8580 Accidental poisoning by hormones and synthetic substitutes  
 
 T500x1D Poisoning by mineralocorticoids and their antagonists, accidental (unintentional), subsequent encounter 
 To  I9 cluster  
   9620 Poisoning by adrenal cortical steroids  
 E8580 Accidental poisoning by hormones and synthetic substitutes  
 
T500x1S Poisoning by mineralocorticoids and their antagonists, accidental (unintentional), sequela 
 To  I9 cluster  
   9090 Late effect of poisoning due to drug, medicinal or biological substance  
 E9292 Late effects of accidental poisoning  
 
How do I read the GEMs?
Adding code descriptions
• ICD-10-CM code descriptions available on NCHS website
– http://www.cdc.gov/nchs/about/otheract/icd9/icd10cm.htm
• ICD-9-CM and ICD-10-PCS code descriptions available on CMS website
– ICD-9-CM
• http://www.cms.hhs.gov/ICD9ProviderDiagnosticCodes/06_codes.asp#TopOfPage
– ICD-10-PCS
• http://www.cms.hhs.gov/ICD10/01m_2009_ICD10PCS.asp#TopOfPage

How do I read the GEMs?
Flags
• Read as 1=On, 0=Off
• Three different flags
– Approximate
– No Map
– Combination

PCS  to	  I-9  + flags
	02733ZZ 0040 10112  
	02733ZZ 0041 10112  
	02733ZZ 0042 10112  
	02733ZZ 0043 10112  
	02733ZZ 0066 10111  
	02733ZZ 3609 10000

How do I read the GEMs?
The Approximate Flag
• Column 1 of the flags
• 1 means the translation is an approximate match
– the majority of alternatives are considered an approximate match
• 0 means the translation is an identical match
– rare in the procedure GEMs
– more common in the diagnosis GEMs
A000 Cholera due to Vibrio cholerae 01, biovar cholerae 
 From and to  0010 Cholera due to vibrio cholerae  
 
A001 Cholera due to Vibrio cholerae 01, biovar eltor 
 From and to  0011 Cholera due to vibrio cholerae el tor  
 
A009 Cholera, unspecified 
 From and to  0019 Cholera, unspecified  
How do I read the GEMs?
The No Map Flag
• Column 2 of the flags
• 1 means there is no plausible translation for the source system code
• 0 means there is at least one plausible translation for the source system code
T500x6A Underdosing of mineralocorticoids and their antagonists, initial encounter 
 To  NoDx
 
T500x6D Underdosing of mineralocorticoids and their antagonists, subsequent encounter 
 To  NoDx
 
T500x6S Underdosing of mineralocorticoids and their antagonists, sequela 
 To  NoDx

How do I read the GEMs?
The Combination Flag
• Column 3 of the flags
• 1 means the complete translation of the source system code requires more than one target system code (cluster, aka combination entry)
• 0 means the complete translation of the source system code is satisfied by one of the target system code alternatives (single entry)
0RG2040 Fusion of 2 or more Cervical Vertebral Joints with Internal Fixation Device, Anterior, Open Approach 
 To  I9 cluster  
   8102 Other Cervical Fusion, Anterior Technique
AND 
     8162 Fusion Or Refusion Of 2-3 Vertebrae 
 or 8163 Fusion Or Refusion Of 4-8 Vertebrae 
AND
 8451 Insertion Of Interbody Spinal Fusion Device

How do I read the GEMs?
Scenario and Choice list	
• Columns 4 and 5 of the flags
• Method for organizing combination entries
• Scenario defines all the possible codes in a cluster
• Choice list organizes the codes into pick lists—one code from each list in a scenario is a cluster

T1500xA Foreign body in cornea, unspecified eye, initial encounter 
 To  I9 cluster  
   9300 Corneal foreign body  
 E914 Foreign body accidentally entering eye and adnexa  
  
T1500xD Foreign body in cornea, unspecified eye, subsequent encounter 
 To  I9 cluster  
   9300 Corneal foreign body  
 E914 Foreign body accidentally entering eye and adnexa  
  
T1500xS Foreign body in cornea, unspecified eye, sequela 
 To  9085 Late effect of foreign body in orifice 

How can I use the GEMs?
Conversion projects
• Convert ICD-9 based applications to native ICD-10 applications
177 Respiratory infections & inflammations w MCC 
178 Respiratory infections & inflammations w CC 
179 Respiratory infections & inflammations w/o CC/MCC 

PRINCIPAL DIAGNOSIS
A0222 Salmonella pneumonia 
A065 Amebic lung abscess 
A15* Respiratory tuberculosis (7 codes) 
A202 Pneumonic plague 
A212 Pulmonary tularemia 
A221 Pulmonary anthrax 
A310 Pulmonary mycobacterial infection 
A420 Pulmonary actinomycosis 
A430 Pulmonary nocardiosis 
A481 Legionnaires' disease 
A5272 Syphilis of lung and bronchus 
B012 Varicella pneumonia 
B052 Measles complicated by pneumonia 

How can I use the GEMs?
Conversion projects
• The GEMs facilitate conversion projects of any size and type
– Large project: I-9 based MS-DRGs being converted to I-10 based MS-DRGs
– Medium project: ICD-9-CM coding guidelines converted to ICD-10-CM coding guidelines
– Small project: Convert ICD-9-CM based diabetes case management document to ICD-10-CM

How can I use the GEMs?
Conversion task: find and replace
• Most applications are composed of logical relationships between lists of ICD-9 codes
• Conversion involves “finding” ICD-9 lists embedded in applications and “replacing” the ICD-9 list with an ICD-10 equivalent list
– Logic of application unchanged
– Goal is to replicate, not modify
– MS-DRGs conversion uses this process

How can I use the GEMs?
Application-specific mapping
• Develop an ICD-10 to ICD-9 mapping (aka crosswalk) that allows data submitted in ICD-10 to be processed using ICD-9 based applications
• The ICD-10 Reimbursement Mappings are an application-specific mapping
– Interim measure while applications are being converted to a native ICD-10 application

How can I use the GEMs?
General reference
• Write training material for ICD-10 coding education
• Develop document improvement program for ICD-10 documentation needs
• Mine the GEMs to understand the translation challenges in clinical/coding areas of particular interest to you

41000 Acute myocardial infarction of anterolateral wall, episode of care unspecified 
 To  I2109 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall  
41001 Acute myocardial infarction of anterolateral wall, initial episode of care 
 To  I2109 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall  
41002 Acute myocardial infarction of anterolateral wall, subsequent episode of care 
 To  I2109 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall  
41010 Acute myocardial infarction of other anterior wall, episode of care unspecified 
 To  I2109 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall  
41011 Acute myocardial infarction of other anterior wall, initial episode of care 
 To  I2109 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall  
 41012 Acute myocardial infarction of other anterior wall, subsequent episode of care 
 To  I2109 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall

How can I use the GEMs?
Which GEM to use
• I-10 to I-9 GEM
– Conversion of application logic containing lists of codes
• I-9 to I-10 GEM
– Research and forecasting of issues
• Both I-10 to I-9 AND I-9 to I-10 GEMs
– Small conversion projects with access to clinical detail beyond the codes
– General education

How can I use the GEMs?
Replication vs. Optimization
• The goal of replication is to produce an I-10 based application that produces essentially the same results as the current I-9 based application
– Translations must be reviewed and finalized, this is not automatic
– MS-DRGs conversion is an example of replication
• The goal of optimization is to produce an I-10 based application that produces optimized results based on the increased detail in I-10
– Much more complex task
• GEMs can be used for both replication and optimization

Where can I find the GEMs?
Diagnosis codes
• Available on NCHS website at
– http://www.cdc.gov/nchs/about/otheract/icd9/icd10cm.htm
• Also on CMS website at
– http://www.cms.hhs.gov/ICD10/02m_2009_ICD_10_CM.asp#TopOfPage

Where can I find the GEMs?
Diagnosis GEMs users guide
• Available on NCHS website at
• Also on CMS website at
– http://www.cms.hhs.gov/ICD10/02m_2009_ICD_10_CM.asp#TopOfPage

Where can I find the GEMs?
Procedure codes
• Available on CMS website at
– http://www.cms.hhs.gov/ICD10/01m_2009_ICD10PCS.asp#TopOfPage

Where can I find the GEMs?
Procedure GEMs users guide
• Available on CMS website at
– http://www.cms.hhs.gov/ICD10/01m_2009_ICD10PCS.asp#TopOfPage

What are the Reimbursement Mappings? 
GEMs vs. Reimbursement Mappings
• In the GEMs, a single I-10 code can be translated to two or more alternative I-9 translations 
– I09.89 Other specified rheumatic heart diseases  has two plausible translation alternatives 
• The reimbursement mapping contains one I-9 translation alternative chosen for reimbursement purposes, based on frequency data

I0989 Other specified rheumatic heart diseases 
 To  3971 Rheumatic diseases of pulmonary valve  
 To  39899 Other rheumatic heart diseases 
 
What are the Reimbursement Mappings? 
GEMs vs. Reimbursement Mappings
• The GEMs are designed to aid in converting applications and systems from I-9 to I-10
– General purpose translation aid
– For “finding and replacing” codes or lists of codes
• The reimbursement mappings are designed to be interposed between data submitted using I-10 codes and legacy systems using I-9 codes, so data can continue to be processed without converting the legacy system to I-10
– Interim measure while systems are being converted

What are the Reimbursement Mappings? 
System conversion vs. Crosswalk

What are the Reimbursement Mappings? 
Development of the mappings
• Initial translation using the I-10 to I-9 GEM
• Where an I-10 code is translated to one I-9 code, no additional review is necessary
– 95% of the I-10 codes are translated to a single I-9 code
– Many 1-10 codes are translated to the same I-9 code
• Where an I-10 code is translated to more than one I-9 code, historical I-9 code frequency data are used to determine the most commonly used I-9 code among the I-9 code alternatives
– MedPAR and OHSPD (for newborn and OB codes) data were used
– In the vast majority of cases there is a clear dominant code in terms of frequency
– In rare cases, clinical review is needed to make the final choice

What are the Reimbursement Mappings? 
Development of the mappings
• Because both MedPAR and OHSPD data sets come from hospital admission data, choosing between I-9 alternatives may reflect frequencies more characteristic of inpatient than outpatient data when the two differ
– Example: complications of pregnancy
• I-10 does not specify whether the patient delivered during the encounter
• The reimbursement mapping must choose between I-9 alternatives
• For inpatient hospital data, the I-9 codes specifying delivery are far more frequent, while in outpatient and physician data, one would expect the I-9 codes specifying antepartum encounter to dominate
• O610 Failed medical induction of labor 
– To 65910 Failed medical or unspecified induction of labor, unspecified as to episode of care  
– To 65911 Failed medical or unspecified induction of labor, delivered  
– To 65913 Failed medical or unspecified induction of labor, antepartum  

What are the Reimbursement Mappings? 
Development of the mappings
• All I-10 codes with an entry in the GEMs are included 
• Each I-10 code is assigned to a single I-9 code or I-9 code cluster 
– I-9 code cluster contains two or more I-9 codes that must be used in combination to attain the complete meaning of one I-10 code

What are the Reimbursement Mappings? 
I-9 code clusters
• Because one ICD-10-PCS code contains a complete description of the procedure, and one ICD-10-CM code may contain both specification of the underlying disease and a current exacerbation or complication, multiple I-9 codes may be necessary to attain the same level of completeness
– ~3% of I-10 codes are assigned to an “I-9 code cluster”
E1036 Type 1 diabetes mellitus with diabetic cataract 
 To  I9 cluster  
   25051 Diabetes with ophthalmic manifestations, type I [juvenile type], not stated as uncontrolled  
   36641 Diabetic cataract

What are the Reimbursement Mappings? 
Mappings format
• Separate files, not part of the GEM files
– Two text files, a diagnosis code reimbursement mapping and a procedure code reimbursement mapping
• Seven-character field for I-10 code
• Up to three, five-character fields for I-9 diagnoses
• Up to five, four-character fields for I-9 procedures

How do I use the Reimbursement Mappings? 
Reading the File
• ICD-10 code on the left side
• Digit in the middle indicates the number of I-9 codes required for a complete translation
• I-9 code or codes on the right side
0273346 5 0066  0043  0048  3607  0044  
027334Z 4 0066  0043  0048  3607  
02733D6 5 0066  0043  0048  3606  0044  
02733DZ 4 0066  0043  0048  3606  
02733Z6 3 0066  0043  0044  
02733ZZ 2 0066  0043

How do I use the Reimbursement Mappings? 
Crosswalk to legacy system
• Designed to be interposed between data submitted using I-10 codes and legacy systems using I-9 codes, so data can continue to be processed using the legacy system
– Interim measure while systems are being converted
S72032A 1 82002 
S72032B 1 82012 
S72032C 1 82012 
S72032D 1 V5413 
S72032E 1 V5413 
S72032F 1 V5413 
S72032G 1 82002 
S72032H 1 82012 
S72032J 1 82012 
S72032K 1 73382 
S72032M 1 73382 
S72032N 1 73382 
S72032P 1 73381 
S72032Q 1 73381 
S72032R 1 73381 
S72032S 1 9053 

How do I use the Reimbursement Mappings? 
Users Guide
• Describes the purpose, the development, how to use and how to customize the mappings
• Appendix A contains technical file format

Where do I find the Reimbursement Mappings? 
Diagnosis AND Procedure mapping
• Both available on CMS website at
– http://www.cms.hhs.gov/ICD10/01m_2009_ICD10PCS.asp#TopOfPage


