Pathology/Lab Coding Alert

Payment may depend on codes that show medical necessity.

With more than 1,500 new and revised ICD-10-CM 2023 codes going into effect later this year, you could use a little help sorting it all out.

Read on as we highlight the relevant changes that could impact pay for your lab and pathology practice.

Why it matters: Medicare and many other payers use ICD-10-CM to process claims, relying on these codes to demonstrate medical necessity for lab and pathology services.

Three ways: Pathologists often assign diagnosis codes based on findings from procedures such as tissue exams, and clinical labs must use current ICD-10-CM codes assigned by the ordering physician to demonstrate medical necessity for ordered tests. Also, Medicare quality reporting programs rely on appropriate diagnosis coding to evaluate appropriate procedures — so missing the boat now could impact your bottom line later.

Anatomic Details Lead Massive Endometriosis Changes

ICD-10-CM 2023 expands the existing nine N80.- (Endometriosis) codes by adding more than 130 new codes. The changes add significant specificity to your diagnosis choices based on anatomic site and tissue depth. “Because pathologists often examine the tissue specimen that culminates in an endometriosis diagnosis, you need to be familiar with these changes,” says R.M. Stainton Jr., MD, president of Doctors’ Anatomic Pathology Services in Jonesboro, Arkansas.

Convert to parent: Starting Oct. 1, the following will be parent codes instead of stand-alone codes:

• N80.0 (Endometriosis of uterus)
• N80.1 (Endometriosis of ovary)
• N80.2 (Endometriosis of fallopian tube)
• N80.3 (Endometriosis of pelvic peritoneum)
• N80.4 (Endometriosis of rectovaginal septum and vagina)
• N80.5 (Endometriosis of intestine)

“To avoid invalid ‘truncated’ codes, you’ll need to stop reporting what will be a ‘parent code’ without the additional fifth and possibly sixth character required to identify the most specific diagnosis for endometriosis of these anatomic sites,” says Terri Brame Joy, MBA, CPC, COC, CGSC, CPC-I, revenue cycle director for Clinical Health Network for Transformation in Houston, Texas.

ICD-10-CM does not convert the following codes to “parent,” but they remain unchanged for 2023:

• N80.6 (Endometriosis in cutaneous scar)
• N80.8 (Other endometriosis)
• N80.9 (Endometriosis, unspecified)

New 4-character codes: Adding more specific anatomic sites where endometriosis may occur, ICD-10-CM creates the following new code families you’ll need to use, effective Oct. 1:

• N80.A- (Endometriosis of bladder and ureters)
• N80.B- (Endometriosis of cardiothoracic space)
• N80.C- (Endometriosis of the abdomen)
• N80.D- (Endometriosis of the pelvic nerves)

Table: Look at the “Clip and Save Endometriosis Dx” table following this article for a breakdown of the new codes.

Prepare Clinical Lab Requisitions for Other New Dx Codes

Labs might see some new ICD-10-CM codes on orders for diagnostic tests once the new codes go into effect, so you need to be familiar with the options. For instance, orders for a microbiology test for a suspected yeast infection, or a cell-count for possible diseases of blood and blood-forming organs, or a test for drug poisoning might include one of the following new diagnosis codes:

• B37.3- (Candidiasis of vulva and vagina) with fifth digit 1 for acute and 2 for chronic
• C84.4- (Peripheral T-cell lymphoma, not classified) with fifth character 1-9 for specific lymph node regions
• D59.3- (Hemolytic-uremic syndrome) with fifth character 0 for unspecified, 1 for infection-associated, 2 for hereditary, and 9 for other
• D68.0- (Von Willebrand disease) with fifth and sixth digits for type
• T43.65- (Poisoning by, adverse effect of and underdosing of methamphetamines) 24 new codes.