Pathology/Lab Coding Alert

Question: I know that I can use modifier59 to unbundle codes under the right circumstances, but which code should I attach it tothe one in column 1 or column 2 of the edits?


New Jersey Subscriber
Answer: You should always append modifier 59 (Distinct procedural service) to the lesser-valued code--regardless of the order in which the pathologist performed the procedures. Depending on what kind of bundle the codes are in, the lesser-valued code may be in column 1 or column 2 of the National Correct Coding Initiative (NCCI) edits.

If the codes are in a "Comprehensive/Component" or "Column 1/Column 2" bundle, such as 80051 (Electrolyte panel) and 82374 (Carbon dioxide [bicarbonate]), NCCI considers the procedure or service in column 2 (82374) as an intrinsic part of the procedure or service in column 1 (80051). You can see why because carbon dioxide is one of the four lab chemistry tests that comprise the electrolyte panel. For these edits, the code in column 2 is usually the lesser-valued one.

In this case, you would leave the column 1 code, 80051, unmodified and report it first. If the lab performed is a medically necessary second carbon dioxide test later in the day, append modifier 59 to the column 2 procedure, 82374, and report it second.

Watch for: In a "mutually exclusive" edit, NCCI does not expect that the two codes would ever be medically necessary together. If you report two mutually exclusive codes together without an appropriate modifier, Medicare carriers will only pay for the code in column 1. And to discourage you from trying to report the two codes together, NCCI places the lesser-valued code in column 1 of the mutually exclusive edits.

Example: A mutually exclusive edit places +88313 (Special stains [list separately in addition to code for primary service]; Group II, all other [e.g., iron, trichrome], except immunocytochemistry and immunoperoxidase stains, each) in column 1 and 88358 (Morphometric analysis; tumor [e.g., DNA ploidy]) in column 2.

To unbundle these two procedures, report 88358 unmodified and append modifier 59 to 88313. You can report these two codes together only if the pathologist performs the special stain and DNA ploidy analysis on two distinct specimens, such as from two separate surgical sites.

Caution: Never use modifier 59 if the modifier indicator for the edit pair is "0." That means you cannot unbundle the codes under any circumstances.