A4771 HCPCS Reimbursement & Policy Benchmarks

HCPCS Level II code A4771 designates a serum clotting time tube furnished for dialysis use and billed in units of 50. This supply item supports anticoagulation monitoring and clotting assessments associated with dialysis treatment, making it a routine component of outpatient hemodialysis operations and dialysis clinics nationwide. Accurate coding for A4771 affects claims processing, supply cost accounting, and clinical documentation workflows for dialysis providers.

Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides a national perspective on how the code is used across payers, typical billing contexts, and the clinical setting where the supply is deployed.

Readers will learn the clinical role of the item identified by A4771, the typical site-of-service applications, and what to expect when submitting claims for this dialysis supply. The report also outlines common modifiers and billing considerations, payer coverage patterns where available, and any relevant policy clarifications. Data not available in the input will be identified as such in the detailed sections.

Billing Code Overview

HCPCS Level II code A4771 describes a serum clotting time tube used for dialysis, packaged and billed per 50. The service type is durable medical/supplies for hemodialysis anticoagulation testing, and the typical site of service is dialysis clinic or outpatient dialysis unit.

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Clinical Context

A common clinical scenario for A4771 involves a hemodialysis clinic or hospital dialysis unit preparing for routine dialysis sessions. A patient with end-stage renal disease arrives for scheduled hemodialysis. The dialysis nurse or technician draws blood samples into specialized serum clotting time tubes to perform coagulation testing before or during the dialysis session to assess anticoagulation status, particularly when heparin dosing is used or when there is concern for bleeding or clotting in the extracorporeal circuit. The serum clotting time tubes are typically stocked in the dialysis unit supply and are used in batches (packaged per 50), with inventory management and billing performed by the facility supply department. Typical workflow steps: supply retrieval and verification, labeling and preparation of tubes, blood draw by trained staff, transport to the on-site or reference laboratory, and documentation of tube lot and quantity used in the patient’s procedure record and supply charge capture for billing.

Coding Specifications

Modifier	Description	When to Use
`00`	No modifier applicable / default	Use when no other modifier applies to the supply charge
`52`

Taxonomy Code	Specialty	Notes
`365100000X`	Nephrology	Dialysis physicians overseeing anticoagulation and dialysis management
`174400000X`	Nurse Practitioner	Advanced practice providers performing vascular access management and specimen collection
`207Q00000X`	Clinical Nurse Specialist	Dialysis nursing specialists supervising quality control and supplies
`363L00000X`	Dialysis Technician	Staff performing blood draws and handling dialysis supplies
`207L00000X`	Registered Nurse	Primary personnel administering hemodialysis and collecting specimens

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`N18.6`	End stage renal disease	Primary indication for maintenance hemodialysis where serum clotting time monitoring is commonly required
`I82.409`	Acute embolism and thrombosis of unspecified deep veins of unspecified lower extremity	Coagulation assessment may be indicated in patients with thrombotic complications related to vascular access or systemic clotting concerns
`D68.9`	Coagulation defect, unspecified	Directly relevant to monitoring coagulation and using clotting time tubes for laboratory assessment
`T82.5XXA`	Thrombosis of vascular prosthetic devices, implants and grafts, initial encounter	Relevant when evaluating clotting in vascular access devices or grafts used for dialysis
`R79.1`	Abnormal coagulation profile	Lab finding that indicates use of clotting time tubes to quantify abnormalities prior to or during dialysis
`I50.9`	Heart failure, unspecified	Common comorbidity in dialysis patients where anticoagulation management may be part of overall care
`Z99.2`	Dependence on renal dialysis	Administrative diagnosis commonly present on dialysis encounters when supplies like `A4771` are used
`Z51.12`	Encounter for dialysis and dialysis catheter care	Encounter code associated with dialysis services and related supply use

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Primary procedure performed when drawing blood into serum clotting time tubes prior to dialysis
`99213`	Office or other outpatient visit for evaluation and management of an established patient, typically 15 minutes	E/M service that may document review of coagulation tests and dialysis anticoagulation plan during a clinic visit
`90935`	Hemodialysis procedure with single evaluation by a physician or other qualified health care professional, for patients three times per week, for individuals requiring dialysis	The dialysis treatment during which coagulation status is monitored and serum clotting time tubes are used
`36416`	Collection of capillary blood specimen (e.g., finger, heel, ear stick)	Alternative specimen collection method when venipuncture is not feasible; sometimes used for point-of-care coagulation checks
`99070`	Supplies and materials (except spectacles), provided by the physician over and above those usually included with the office visit or procedure	Used to report additional non-billable supplies when payer policies require explicit supply charge reporting; relates to billing the serum clotting time tubes when payer requires supply-level charges

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Summary & Overview

HCPCS A4771: Serum Clotting Time Tube for Dialysis, per 50