“The devil is in the details”!  The “Random House Dictionary of Popular Proverbs and Sayings” shows this phrase as a variation of “God is in the details,” meaning that whatever one does should be done thoroughly; details are important. The saying is generally attributed to Gustave Flaubert (1821-80), who is often quoted as saying, “Le bon Dieu est dans le detail” (God is in the details).

This expression refers to a catch or mysterious element hidden in the details and implies that overlooking the smallest detail might cause failure. Even the most complex project depends on the success of the smallest components.  ICD-10 diagnosis coding will build on details we are familiar with and new code detail and guidelines we have not previously encountered.  Small things in your strategy plan, if overlooked, can result in big problems later on. 

The ICD-10 is copyrighted by the World Health Organization (WHO), which owns and publishes the classification.  On December 22, 2010, the Center for Medicare and Medicaid Services (CMS) posted the updated ICD-10-CM code set to their website.  The ICD-10 codes are currently in draft form and there will be changes and additions prior to the final live date on October 1, 2013.  It would be prudent to obtain a draft ICD-10 diagnosis manual to familiarize yourself with the guidelines, structure and conventions. 

Additional detail may also be found under the ICD-10 category codes in the tabular list

Additional detail may also be found under the ICD-10 category codes in the tabular list as an “includes” note.  An example of this convention is category I21, acute myocardial infarction, which states “includes a myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset”.  This differs from ICD-9 where category 410 states “an acute MI is acute for 8 weeks”. 

For example, code I21.01 ST elevation (STEMI) myocardial infarction involving left main coronary artery translates to an acute MI.  If the patient is seen post-discharge from the hospital at 18 days from onset of the heart attack, it is still considered an acute MI.  If the patient is seen on day 29 following an acute MI, with no additional complaint or complication, the ICD-10 code would be an old MI code I25.2 (healed myocardial infarction).

Category I22  Subsequent ST Elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction. This category has the following instructional note:  “A code from category I22 must be used in conjunction with a code from category I21. The I22 code should be sequenced first, if it the reason for encounter, or, it should be sequenced after the I21 code if the subsequent MI occurs during the encounter for the initial MI”.  For example: code I22.0, Subsequent ST elevation (STEMI) myocardial infarction of anterior wall.

Category I23 Certain current conditions following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period).  There is a note under this category code stating: “A code from category I23 must be used in conjunction with a code from category I21 or category I22. The I23 code should be sequenced first, if it is the reason for encounter, or, it should be sequenced after the I21 or I22 code if the complication of the MI occurs during the encounter for the MI”.  Code I23.7 describes postinfarction angina, as an example of a complication.

The ICD-10 code sets have significant changes in structure and concepts that make them very different from ICD-9. The category codes for a heart attack (myocardial infarction) are an example of these differences. It is important to develop a preliminary understanding of the changes from ICD-9 to ICD-10 diagnosis codes.  If unfamiliar with clinical terms, such as STEMI or NSTEMI, the professional coder should query the physician or research the definitions. 

STEMI (ST segment elevation myocardial infarction) indicates the patient has signs of a heart attack.  If a portion of heart muscle was damaged, the electrocardiogram (ECG) tracing shows an elevation of the ST segment, and this “ST Elevation” is considered an indication of a heart attack.  In the case of a non-ST elevation heart attack (NSTEMI), the symptoms of chest pain can be identical to that of a STEMI, but the important difference is that the patient’s electrocardiogram does not show the typical ST elevation changes traditionally associated with a heart attack.

Diagnosis codes are to be used and reported at their highest number of digits available

Diagnosis codes are to be used and reported at their highest number of digits available. ICD-10-CM diagnosis codes are composed of codes with 3, 4, 5, 6 or 7 digits. Codes with three digits are included in ICD-10-CM as the heading of a category of codes that may be further subdivided by the use of fourth and/or fifth digits, which provide greater detail. A three-digit code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if applicable.

Chapter 15 of ICD-10 (Pregnancy, Childbirth and the Puerperium O00-O99) includes greater detail than similar conditions in the ICD-9 coding classification.  These codes are used only on maternal records, never on a newborn’s record.  In ICD-9 many codes in Chapter 11 (Complications of Pregnancy, Childbirth and the Puerperium) required a 5^th digit to denote the episode of care (antepartum, postpartum, delivered).  ICD-10 replaces “episode of care” with “trimester”. Trimesters are counted from the first day of the last menstrual period. They are defined as follows: 1st trimester – less than 14 weeks 0 days; 2nd trimester – 14 weeks 0 days to less than 28 weeks 0 days; 3rd trimester – 28 weeks 0 days until delivery. Code O24.112 describes, Pre-existing diabetes mellitus, type 2, in pregnancy, second trimester.

Chapter 15 requires 7 digits in many code definitions.  An example of this is an encounter with the mother for disproportion due to an unusually large fetus (O33.5).  This diagnosis could be the reason for observation, hospitalization or other obstetric care of the mother, or for cesarean delivery before onset of labor.  A 7th character is to be assigned to each code under category O33. The 7th character 0 is for single gestations and multiple gestations where the fetus is unspecified. 7th characters 1 through 9 are for cases of multiple gestations to identify the fetus for which the code applies. The appropriate code from category O30 (Multiple gestation) must also be assigned when assigning a code from category O35 that has a 7th character of 1 through 9.  If the patient presents with a single gestation the appropriate 7^th digit is 0 (O33.5xx0).  Subcategory O33.5 does not have a 5^th or 6^th digit but requires a 7^th digit.  In this case, it is necessary to use two placeholders (xx) in the 5^th and 6^th place followed by the 7^th digit of 0 to denote a single gestation.

If the patient presents in the third trimester with twin gestation and disproportion involving fetus 2, the appropriate code assignments would be: O33.5xx2 and O30.003 (twin pregnancy, unspecified, third trimester).

The devil is in the detail when assigning ICD-10 diagnosis codes.  Documentation must support the condition(s) coded and physicians must be educated on the detail required.  This is a new way of doing business and everyone involved must be prepared, patient, and willing to adapt.  Resistance will yield frustration and accomplish nothing meaningful on the path to compliance.

 
Nancy Maguire, ACS, PCS, FCS, HCS-D, CRT, author of The Nancy Maguire GPS to ICD-10-CM Planning and Implementation Guide, is a nationally-renowned procedural and diagnostic coding instructor, bootcamp trainer, and workshop leader. She has spent more than 30 years as a hands-on coder and has authored countless coding articles and presentations. In her expansive career, she has transitioned from nursing, to coding, to practice management, auditing and consulting. Nancy served as Director of Coding and Reimbursement at UTMB in Galveston Texas for four years. She served the first two terms as president of AAPC in the early 1990s.

Nancy will be speaking in a complimentary webinar presented by Kareo medical billing software on “Preparing for ICD-10-CM: The Nitty-Gritty of Diagnosis Coding” on June 16th. Register now.