FAQ 1.  What is ICD-10-CM?

ICD-10-CM is the long awaited diagnosis code set revision to ICD-9-CM.  There is another code set known as ICD-10-PCS (Procedure Coding System).  ICD-10-PCS will be discussed in FAQ 6 below.  

The International Classification of Diseases (ICD) is the copyrighted official publication of the World Health Organization (WHO). The primary purpose of ICD is for epidemiological tracking of illness and injury. ICD has been used in the US since 1949 (ICD­6). The first formal US adaption was by the US Public Health Service with ICD­7. The current US adaptions are controlled by the "cooperating parties": National Center for Health Statistics/CDC (NCHS), Centers for Medicare and Medicaid Services (CMS), American Hospital Association (AHA), and American Health Information Management Association (AHIMA).

FAQ 2.  What is the implementation date for ICD-10?

On July 31, 2014, the U.S. Department of Health and Human Services issued a final rule finalizing October 1, 2015 as the new compliance date to transition to the ICD-10 code sets. The rule also requires HIPAA covered entities to continue to use ICD-9-CM through September 30, 2015.

FAQ 3.  Why do we need ICD-10-CM?

Frankly, ICD-9-CM is running out of codes. Hundreds of new diagnosis codes are submitted by medical societies, quality-monitoring organizations and others annually. ICD-10-CM will allow not only for more codes but also for greater specificity and thus better epidemiological tracking. This will allow providers to better identify certain patients with specific conditions that will benefit from tailored disease management programs, e.g. diabetes, hypertension, asthma. 

FAQ 4.  How are ICD-9 and ICD-10 different?

The ICD-10-CM codes are very different from those currently used in ICD-9-CM. All codes in ICD-10-CM are alphanumeric. There may be up to seven alphanumeric characters, requiring billing software program changes to accommodate the additional digits, as well as extensive coder training. ICD-10-CM will have greater specificity (i.e. granularity) along with laterality (anatomic location). Specialty societies had significant input in the development of the depth of detail they wanted to enable the tracking of certain conditions and injuries.  Given the increased level of coding specificity required by ICD-10, it is anticipated the degree of documentation required by physicians will also increase.

ICD-10-CM codes will be able to provide more in depth information about the patient's condition that can be more easily captured in an electronic medical record. Physician (HCFA 1500) and hospital (UB-04) billing forms have been updated to accommodate the changes.





Precordial Chest Pain




Asthma, Acute Exacerbation




Thumb laceration




Thumb, w/o nail damage, initial encounter



Laceration w/o FB, right thumb, initial encounter, OR




Laceration w/o FB, left thumb, initial encounter, OR




Laceration w/o FB, unspecified thumb, initial encounter

*Just as with ICD-9-CM, clear physician documentation will be important to aid in assigning appropriate ICD-10-CM codes.

FAQ 5.  What is GEM?

General Equivalence Mappings (GEM) were developed by NCHS and CMS, with collaboration of AHIMA and AHA, as a tool to assist with the conversion from ICD-9-CM codes to ICD-10-CM and the conversion of ICD-10-CM codes back to ICD-9-CM. The GEMs are forward and backward mappings between the ICD-9-CM and ICD-10-CM coding systems and are used to help develop crosswalks that provide important information linking codes of one system with codes in the other.

In some instances, there is not a translation between an ICD-9-CM code and an ICD-10-CM code. When there is no plausible translation from a code in one system to a code in the other system, a "No Map" flag indicator is noted.

FAQ 6.  What is ICD-10-PCS?

ICD-10-PCS (Procedure Coding System) is currently designated to replace Volume 3 of ICD-9-CM for hospital inpatient use. PCS is ONLY for hospital use at this time. CMS has stated ICD-10-PCS is not intended to replace CPT.

CPT remains the procedure-coding standard for physicians, regardless of whether the physician services were provided in the inpatient or outpatient setting. Any third party payer asking for Volume 3 procedure codes to be submitted along with CPT codes for outpatient services is in violation of HIPAA regulations and subject to fines by CMS.

Some preliminary inpatient hospital testing of ICD-10-PCS has indicated that the new procedure coding system is problematic to learn for both experienced and inexperienced coders.

FAQ 7.  What are the estimated costs for adopting the new ICD-10 coding systems?

There have been many questions as to the cost of implementing ICD-10. The RAND Science and Technology Policy Institute is publishing its findings on the cost and benefits of implementing ICD-10. According to the draft executive summary, providers will incur costs for computer reprogramming, the training of coders, physicians, and code users, and for the initial and long-term loss of productivity among coders and physicians. The cost of sequential conversion (10-CM then 10-PCS) is estimated to run $425M to $1.15B in one-time costs plus somewhere between $5 and $40 million a year in lost productivity.

RAND assumes the benefits as largely coming from the additional detail that ICD-10-CM and ICD-10-PCS would offer. The benefit of more accurate payments to hospitals for new procedures ranges from $100M to $1.2B. Benefits from fewer rejected claims would be $200M to $2.5B and $100M to $1B for fewer exaggerated claims. The identification of more cost-effective services and direction of care to specific populations would result in a benefit of $100M to $1.5B. This is in addition to any benefits that would come from better total disease management and better directed preventive care.

Blue Cross and Blue Shield sponsored a study to determine costs to the health care industry in adopting ICD-10-CM and ICD-10-PCS. The study indicated a cost range of $5.5-13.5 billion for systems implementation, training, loss of productivity, re-work, and contract re-negotiations during a 2-3 year implementation period. Over half of the costs would be borne by health care providers. Long-term recurring costs for loss of productivity were estimated at $150 million to $380 million. However, both hospitals and third party payers have already made extensive investments in preparation for the October 1, 2014 scheduled change over. 

FAQ 8.  How is ICD-10 organized?  

The ICD-10-CM code set contains an alphabetic Index to Diseases and Injuries, a Neoplasm Table, a Table of Drugs and Chemicals, Index to External Causes, and 21 chapters in the Tabular List of Diseases and Injuries.  The table below provides ICD-10-CM tabular chapter subjects and corresponding alphanumeric code ranges.


 Alpha Numeric

1. Certain Infectious and Parasitic Diseases


2. Neoplasms  


3. Blood and Blood-forming Organs


4. Endocrine, Nutritional and Metabolic Diseases  


5. Mental, Behavioral, and Neurodevelopmental Disorders  


6. Nervous System  


7. Eye and Adnexa  


8. Ear and Mastoid Process  


9. Circulatory System  


10. Respiratory System  


11. Digestive System  


12. Skin and Subcutaneous Tissue  


13. Musculoskeletal System and Connective Tissue  


14. Genitourinary System  


15. Pregnancy, Childbirth and the Puerperium  


16. Certain Conditions Originating in the Perinatal Period  


17. Congenital Malformations, Deformations and Chromosomal Abnormalities  


18. Symptoms, Signs and Abnormal Clinical and Laboratory Findings  


19. Injury, Poisoning and Certain Other Consequences of External Causes  


20. External Causes of Morbidity  


21. Factors Influencing Health Status and Contact with Health Services  


FAQ 9.  Where can I learn more about ICD-10-CM and ICD-10-PCS?

FY 2015 ICD-10-CM Guidelines, GEM, and code set data files are located at: 


Additional resources are located on the ACEP website: 

ICD-10-CM and the Emergency Physician

ICD-10-CM For the Busy Emergency Physician

ICD-10-CM ED Clinical Examples

The following list provides examples of ICD-9-CM codes frequently used in Emergency Medicine, and approximate ICD-10-CM equivalents:


 ICD-10-CM Description






 Alcohol abuse with unspecified alcohol-induced disorder



 Major depressive disorder, single episode, unspecified



 Anxiety disorder, unspecified



 Epilepsy, unspecified, not intractable, without status epilepticus



 Migraine, unspecified, not intractable, without status migrainosus



 Conjunctivitis, unspecified



 Otitis media, unspecified, right ear



 Hypertension NOS



 Non-ST elevation (NSTEMI) myocardial infarction



 Atrial fibrillation, unspecified



 Transient cerebral ischemic attack, unspecified



 Acute pharyngitis, unspecified



 Acute upper respiratory infection, unspecified



 Pneumonia, unspecified organism



 Chronic obstructive pulmonary disease with (acute) exacerbation



 Asthma, unspecified with (acute) exacerbation



 Non-infective gastroenteritis and colitis, unspecified



 Cellulitis of left lower limb



 Pain in right knee



 Low back pain



 Pain in left upper arm



 Pain in right forearm



 Pain in left thigh



 Pain in right lower leg



 Calculus of kidney



 Urinary tract infection, site not specified



 Unspecified infection of urinary tract in pregnancy, second trimester









 Shortness of breath



 Chest pain on breathing



 Chest pain, Other



 Chest pain, unspecified



 Epigastric pain



 Abdominal pain, upper, unspecified



 Abdominal pain, lower, unspecified



 Nausea with vomiting, unspecified



 Diarrhea, unspecified



 Dizziness and giddiness



 Fever, unspecified






 Malaise, other



 Fatigue, other



 Syncope and collapse



 Contusion of unspecified part of head, initial encounter



Poisoning by anticoagulants (e.g. warfarin), accidental (unintentional) initial encounter



Poisoning by selective serotonin and norepinephrine reuptake inhibitors, intentional self-harm initial encounter


 No Code

Underdosing of hydantoin derivatives (e.g. Dilantin), initial encounter



Unspecified open wound of other part of head, initial encounter



Injury, head, unspecified, initial encounter



Sprain of ligaments of cervical spine, initial encounter



Unspecified open wound of right ring finger without damage to nail, initial encounter



Sprain of unspecified ligament of left ankle, initial encounter



Encounter for removal of sutures



Encounter for examination and observation following alleged rape



Car driver injured in collision with car, pick-up truck or van in traffic accident initial encounter




Pedestrian on foot injured in collision with pedal cycle in traffic accident initial encounter




Fall on same level from slipping, tripping and stumbling with subsequent striking against sharp glass initial encounter


 FAQ 10. Are "unspecified" diagnosis codes permitted with ICD-10-CM?

A. Yes, these types of codes are permitted when a more specific diagnosis is not available at the time of the encounter. For example, if the patient is diagnosed with a pneumonia but the physician is not able to determine additional detail than "Pneumonia, organism unspecified" (J18.9) is a permissible diagnosis. However, if the pneumonia was associated with aspiration of vomit (J69.0) or Avian influenza (J09.X1), then those specific codes would be used.

Specificity is of particular importance, for example, as to the location of an injury, abdominal, back or limb pain. A specific diagnosis should indicate if an injury was of the left/ right forearm or upper arm or 3rd digit finger as opposed to non-specific term "arm" or "finger."

The [ICD] Official Guidelines for Coding and Reporting says:

Signs/symptoms and "unspecified" codes have acceptable, even necessary, uses. While specific diagnosis codes should be reported when they are supported by the available medical record documentation and clinical knowledge of the patient's health condition, there are instances when signs/symptoms or unspecified codes are the best choices for accurately reflecting the healthcare encounter. Each healthcare encounter should be coded to the level of certainty known for that encounter.

If a definitive diagnosis has not been established by the end of the encounter, it is appropriate to report codes for sign(s) and/or symptom(s) in lieu of a definitive diagnosis. When sufficient clinical information isn't known or available about a particular health condition to assign a more specific code, it is acceptable to report the appropriate "unspecified" code (e.g., a diagnosis of pneumonia has been determined, but not the specific type). Unspecified codes should be reported when they are the codes that most accurately reflect what is known about the patient's condition at the time of that particular encounter. It would be inappropriate to select a specific code that is not supported by the medical record documentation or conduct medically unnecessary diagnostic testing in order to determine a more specific code. (underline added)

This information was also published in Coding Clinic, Second Quarter 2013, pages 29-30.

Payers may need to be reminded, "Adherence to these guidelines when assigning ICD-9-CM diagnosis and procedure codes is required under the Health Insurance Portability and Accountability Act (HIPAA)."  (ICD-9-CM Official Guidelines for Coding and Reporting)

 Last Updated 4/21/2015

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