ICD-10 Basics

ICD-10 Basics

How are ICD-10 codes structured?

They are 3-7 digits in length

  • Digit 1 is alpha

  • Digit 2 is numeric

  • Digits 3-7 are alpha or numeric

A decimal is used after the third character

The expanded number of characters provides greater specificity to identify disease etiology, anatomic site, and severity

  • Characters 1-3 = Category

  • Characters 4-6 = Etiology, anatomic site, severity, or other clinical detail

  • haracter 7 = Extension

The following example shows the more detailed information gained through the added characters, only the last code is reportable

  • S52 = Fracture of forearm

  • S52.5 = Fracture of lower end of radius

  • S52.52 = Torus fracture of lower end of radius

  • S52.521 = Torus fracture of lower end of right radius

  • S52.521A = Torus fracture of lower end of right radius, initial encounter for closed fracture

What is different in ICD-10?

1)  Increased level of specificity inherent in the codes, particularly with fractures

2)  Inclusion of clinical concepts that do not exist in ICD-9 such as under dosing, blood type, and blood alcohol level

3)  Laterality is now built into the code, example:

  • M25.551 = Pain in right hip

  • M25.552 = Pain in left hip

4)  Episode of care (7th Digit) required for most injuries/fractures etc.

  • A = Initial encounter

  • D = Subsequent encounter

  • S = Sequela (Subsequent conditions that arise as a result of the injury)

  • Example: S92.311D = Displaced fracture of 1st metatarsal, right foot, subsequent encounter

5)  Character “X” is used as a 5th and/or 6th digit placeholder to fill empty spaces if a shorter code requires a seventh digit, example:

  • Foreign body in cornea, left eye, subsequent encounter

  • T15.02XD = Correct

  • T15.02D = Incorrect

6)  Combination codes for certain conditions and common associated symptoms and manifestations. Combination codes allow for the reporting of a single code to express multiple elements of the diagnosis, example:

  • E11.321 = Type 2 diabetes mellitus with mild nonproliferative diabetic retinopathy with macular edema

  • E11.341 = Type 2 diabetes mellitus with severe nonproliferative diabetic retinopathy with macular edema

7)  Combination codes for poisonings include the associated external cause, ex:

  • T42.3X2A- Poisoning by barbiturates, intentional self-harm, initial encounter

8)  Obstetric codes identify trimester instead of episode of care, example:

  • O26.02 = Excessive weight gain in pregnancy, second trimester

  • O26.03 = Excessive weight gain in pregnancy, third trimester

9)  Codes for postoperative complications are expanded and a distinction is made between intraoperative complications and postprocedural disorders


Use of external cause and unspecified codes in ICD-10

Similar to ICD-9, there is no national requirement for external cause code reporting.

  • In some instances, signs/symptoms or unspecified codes may be the only choice to accurately reflect the health care encounter, but they should only be reported if a more specific alternative does not exist. 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. Each health care encounter should be coded to the level of certainty known for that encounter.

What can you do to help ensure most specific ICD-10 codes are selected?

  • Start familiarizing yourself with the new codes for your most commonly used diagnoses.

  • Be sure to include laterality! In order to avoid unnecessary claim denials, document the condition location on both the superbill and in your notes.

  • Be specific on your billing forms! The more information you provide on a billing sheet, the better chance we have of finding the most specific ICD-10 code. A condition for which you may have previously used an ICD-9 unspecified code may now be specifically coded under ICD-10. If you believe an unspecified code is still appropriate, write the condition down on the superbill so we can check.

Brandon McCurdy