Summary & Overview
CPT 84620: D‑xylose (Xylose) Absorption Test
CPT code 84620 denotes the technical laboratory measurement of D–xylose (xylose) in blood and/or urine to evaluate carbohydrate absorption in patients with suspected malabsorption. This test is clinically relevant for assessing small‑bowel mucosal function and can inform diagnostic pathways for conditions such as celiac disease, bacterial overgrowth, or other causes of impaired carbohydrate uptake. Nationally, laboratory utilization and coverage policies for this assay affect both ambulatory and inpatient diagnostic workflows and have implications for lab billing and coding compliance.
Key payers commonly involved in coverage and payment considerations include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context, typical sites of service, common billing considerations, and the payer landscape. The publication provides benchmark and policy context where available, explains clinical indications that drive test ordering, and outlines how this laboratory service is positioned within diagnostic evaluation of malabsorption. Data not available in the input will be noted where relevant.
Billing Code Overview
CPT code 84620 describes a laboratory technical service that measures D–xylose (xylose) levels in blood and/or urine. This assay is used to evaluate carbohydrate absorption in patients who present with symptoms of malabsorption, such as chronic diarrhea, weight loss, or suspected small‑bowel mucosal disease.
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Service type: Laboratory diagnostic test — quantitative measurement of D–xylose in serum and/or urine.
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Typical site of service: Clinical laboratory, hospital laboratory, or outpatient phlebotomy/collection site where specimens are processed and analyzed.
Clinical & Coding Specifications
Clinical Context
A 42-year-old patient presents to the gastroenterology clinic with a 3-month history of progressive bloating, chronic diarrhea, unexplained weight loss, and iron-deficiency anemia. The gastroenterologist suspects a malabsorption disorder and orders a D-xylose absorption test to evaluate proximal small intestinal carbohydrate absorption. The patient is instructed to fast overnight and to discontinue interfering medications per lab instructions. On the day of testing, baseline blood is drawn, the patient ingests a measured oral dose of D-xylose, and timed blood and/or urine specimens are collected at specified intervals. The laboratory performs the technical assay to measure D-xylose concentration in serum and/or urine, generating quantitative results reported to the ordering provider. Results are interpreted in the clinical context of other studies (stool studies, celiac serologies, endoscopic biopsies) to differentiate mucosal disease (for example, celiac disease or tropical sprue) from pancreatic insufficiency or bacterial overgrowth as causes of malabsorption.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the physician interpretation on the test if the technical component is billed separately. |
59 |