Pathology/Lab Coding Alert

Question: When using ICD-9 diagnosis codes , I've been told to be cautious about reporting "truncated codes." Can you explain what that means, and why and how to avoid the practice?

Iowa Reader

Answer: Your adviser is right to caution you about reporting truncated diagnosis codes, because they can result in claim denials.

ICD-9 contains codes with three, four or five digits. Most three-digit codes serve as headings for broad categories, which need to be further divided. Categories are subdivided by adding a decimal point as well as a fourth and/or fifth digit after the third digit. The fourth and fifth digits provide more detail about the nature of the disease or condition. Those codes with fourth digits are called subcategory codes, while those with fifth digits are subclassifications. The rule is, if a fourth or fifth digit is available, you must use it.

Assigning a "truncated code" means reporting fourth- and fifth-digit codes only to the third or fourth digit, respectively. As the Official ICD-9-CM Guidelines for Coding and Reporting explains, "A code is invalid if it has not been coded to the full number of digits required for that code."

For example, if a pathologist bills for evaluation of a gallbladder (88304, Level III - Surgical pathology, gross and microscopic examination, gallbladder), truncated code 574.x (Cholelithiasis) would not be an acceptable diagnosis. You have to report gallstones to the fifth digit based on the location of the calculus, and the presence, absence, or character of inflammation, and the nature of obstruction. Report the most specific code that describes the condition, such as 574.01 (Calculus of gallbladder with acute cholecystitis) for an acutely-inflamed, obstructive cystic-duct gallstone.

Reader Questions and You Be the Coder were answered and/or reviewed by R.M. Stainton Jr., MD, president of Doctors' Anatomic Pathology Services in Jonesboro, Ark.; Laurie Castillo, MA, CPC, CPC-H, CCS-P, president of Physician Coding and Compliance Consulting in Manassas, Va.; and William Dettwyler, MT-AMT, coding analyst for Health Systems Concepts, laboratory and coding compliance consultants in Longwood, Fla.