ICD-10-CM codes will be 3 – 7 alphanumeric characters.  Diseases of the Circulatory System will be coded with codes from the I00-I99 section.  (That’s letter I, not number 1).

One of the most confusing aspects of ICD-10-CM is the use of the placeholder “X”.  Some codes will require a 6th or 7th character but not have a 5th or 6th character, the X will take the place of the missing code.  For instance, in the drug toxicity code section (T36-T65), codes require a 7th character to indicate encounter (initial, subsequent, sequel).  Not all of the base codes in this section have 6 previous characters, so X would be needed to fill in.   Let’s look at toxicity from calcium-channel blockers.  There are 18 codes in this T46.1 subcategory – 12 for poisoning, 3 for adverse reaction and 3 underdosing.  Sixth and 7th characters are used to indicate type of toxicity and encounter.  However, the base code only has 4 characters so the X is used to fill in for the 5th character.  You can see from the following 2 codes how this works.  Both are initial encounter for toxicity from calcium-channel blockers.  T46.1X2A is poisoning by calcium-channel blockers, intentional self-harm, initial encounter and T46.1X5A is adverse effect of calcium-channel blockers, initial encounter.

The long-standing timeframe for acute myocardial infarction will be changed in ICD-10-CM from 8 weeks to just 4 weeks.  Acute myocardial infarction will be coded from category I21.  Official Guidelines for ICD-10-CM include the following guidance: “For encounters after the 4 weeks time frame and the patient requires continued care related to the myocardial infarction, the appropriate aftercare code should be assigned, rather than a code from category I21. Otherwise, code I25.2, Old myocardial infarction, may be assigned for old or healed myocardial infarction not requiring further care.”  The 2011 version of ICD-10-CM Official Guidelines may be found at http://www.cdc.gov/nchs/data/icd9/10cmguidelines2011_FINAL.pdf.

The new system will include some combination codes we’ve not seen before.  For instance, subcategory I25.11 will be used for atherosclerotic heart disease of native coronary artery with angina pectoris.  It will not be necessary to add a second code for the angina pectoris.  A causal relationship is assumed unless the documentation specifically indicates that the angina is due to something other than atherosclerosis.   The I25.7 subcategory will cover atherosclerosis of coronary artery bypass graft(s) and coronary artery of transplanted heart with angina pectoris.

Complication codes will be much more specific in ICD-10-CM.  Two examples of this are I97.410 – Intraoperative hemorrhage and hematoma of a circulatory system organ or structure complicating a cardiac catheterization, vs I97.610 – Postprocedural hemorrhage and hematoma of a circulatory system organ or structure following a cardiac catheterization.

Major changes are coming our way.  But by beginning to get familiar with the changes now, instead of waiting until the last moment, we can lessen the impact.  ICD-10-CM is coming, we can’t stop it, but we can prepare ourselves.


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