Summary & Overview

CPT 85175: Time-to-Lysis (Clot) Laboratory Assay

CPT code 85175 represents a laboratory diagnostic test that measures the time to lysis of a blood clot. This in vitro assay evaluates fibrinolytic activity and clot stability, supporting clinical decision-making in bleeding, thrombotic, and perioperative contexts. The code is used by hospital and clinical laboratories for analytical reporting and billing.

Key payers included in the national analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for the assay, typical sites of service where the procedure is performed, and the common payer landscape relevant to coverage and claims submission. The publication also outlines the typical service classification and what to expect in terms of billing practice, common modifiers, and where to locate policy updates.

This summary provides national-level context for laboratory managers, coding professionals, and policy analysts interested in how CPT code 85175 is applied across payer contracts and clinical workflows. Data not available in the input is noted where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareCPT 85175laboratoryfibrinolysisclot lysis timeclinical laboratorydiagnostic testhematologylaboratory billingpathology

Billing Code Overview

CPT code 85175 describes a laboratory procedure in which a laboratory analyst evaluates a blood specimen to determine the time to lysis (the time it takes for a clot to break down). This test assesses the stability and breakdown characteristics of a clot in vitro and can inform assessments of fibrinolytic activity.

Service type: Laboratory diagnostic test
Typical site of service: Clinical laboratory or hospital laboratory setting

The description above reflects the clinical purpose and usual testing environment for CPT code 85175. Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult admitted for evaluation of a suspected clotting disorder or an abnormal coagulation profile after thrombolytic therapy, transfusion, or surgical hemostatic event. A phlebotomist draws a blood specimen which is sent to the hospital or reference laboratory; a laboratory analyst performs a fibrinolysis or clot stability assay to determine the time to lysis (breakdown) of the clot, coded as 85175. The clinical workflow includes specimen collection, labeling, transport to the coagulation laboratory, processing (centrifugation and preparation of plasma or whole blood as required), initiation of the lysis assay under controlled conditions, timed observations or instrumented readouts, result verification by a technologist, and reporting to the ordering clinician (hematology, surgery, or transfusion medicine). Typical indications include evaluation of hyperfibrinolysis after major trauma, assessment of thrombolytic therapy effectiveness, monitoring of antifibrinolytic therapy (for example tranexamic acid), and investigation of unexplained bleeding or clotting abnormalities. The usual site of service is a hospital clinical laboratory or independent reference laboratory; testing may be ordered by hematology, anesthesia, surgery, or the emergency department and results are used to guide hemostatic management, transfusion decisions, or further diagnostic workup.

Coding Specifications

Modifiers selected reflect those most applicable to laboratory testing, professional/technical components, unusual circumstances, and billing adjustments for 85175.

Modifier	Description	When to Use
`26`	Professional component	When billing the physician or laboratorian interpretation component separately from the technical component.
`TC`	Technical component	When billing the laboratory instrumentation, supplies, and technical work separate from the professional interpretation.
`90`	Reference (outside) laboratory	When testing is performed by an outside reference laboratory and billing must indicate outside lab processing.
`52`	Reduced services	When the test is partially performed or scope is reduced compared to full CPT definition.
`53`	Discontinued procedure	If testing was started but discontinued due to sample issues or patient condition.
`59`	Distinct procedural service	Note: `59` is not in the provided modifier list; therefore do not use.
`62`	Two surgeons	Applicable rarely; use when two surgeons are billing for concurrent operative services that precipitated testing (limited relevance).
`78`	Return to operating room for related procedure during postoperative period	Used when repeat operative intervention leads to additional laboratory testing related to that return.
`80`	Assistant surgeon	When an assistant surgeon is involved in the operative care that generated the specimen and separate billing applies.
`AS`	Physician assistant, nurse practitioner, or clinical nurse specialist services for Medicare	When a non-physician practitioner bills for professional interpretation under Medicare rules.
`QK`	Medical direction of two or three qualified individuals	When the physician directs multiple concurrent services that include interpretation of the test.
`QX`	Modifier for CRNA services (when applicable)	When a certified registered nurse anesthetist is billing for services related to perioperative care that prompted the test.
`QY`	Medical direction of one CRNA by an anesthesiologist	When medical direction relates to services surrounding the testing context.
`U1`	Lab-specific payer modifier (example state/local)	When a payor requires a specific laboratory modifier code tied to local billing rules.

Taxonomy Code	Specialty	Notes
207RH0000X	Hematology	Hematologists order and interpret coagulation and fibrinolysis testing.
208D00000X	Pathology	Pathologists oversee clinical laboratory testing and quality assurance.
362A00000X	Nurse Anesthesiology	Anesthesia providers frequently order intraoperative coagulation testing.
208000000X	Clinical Laboratory	Clinical laboratory directors and medical technologists perform and bill technical testing.
2084P0800X	Transfusion Medicine	Specialists in transfusion medicine interpret results for blood product management.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`D68.0`	Disseminated intravascular coagulation (DIC)	DIC presents with abnormal clot formation and fibrinolysis; clot lysis time helps assess fibrinolytic activity.
`D69.5`	Secondary thrombocytopenia	Bleeding disorders with platelet abnormalities may prompt coagulation and lysis testing.
`I74.9`	Arterial embolism and thrombosis, unspecified	Thrombotic events being evaluated for fibrinolysis effectiveness or to monitor therapy.
`I26.9`	Pulmonary embolism without acute cor pulmonale	Evaluation of thrombolytic therapy effectiveness can include clot lysis testing.
`T78.2`	Anaphylactic shock, unspecified	Severe reactions during transfusion or surgery with bleeding complications may necessitate coagulation testing.
`Z79.01`	Long term (current) anticoagulation therapy	Patients on anticoagulants who develop bleeding or require monitoring may have lysis-time testing as part of evaluation.
`S36.309A`	Injury of other intra-abdominal organ, unspecified, initial encounter	Trauma patients with hemorrhage frequently require coagulation and fibrinolysis testing.
`O74.89`	Other complications of anesthesia during labor and delivery	Peripartum bleeding or coagulopathy evaluation can include clot lysis assays.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`85610`	Prothrombin time; plasma or whole blood using coagulometer	Common complementary coagulation screening test ordered alongside clot lysis time to assess overall coagulation status.
`85730`	Thrombin clotting time; plasma	Related coagulation assay assessing fibrinogen function and thrombin-mediated clot formation, helpful when interpreting lysis results.
`86140`	Fibrinogen antigen (e.g., immunologic assay)	Quantifies fibrinogen level which affects clot stability and lysis time interpretation.
`85576`	Thromboelastography (TEG) or rotational thromboelastometry (ROTEM)	Provides dynamic global assessment of clot formation and breakdown; often ordered in the same clinical scenarios as `85175`.
`99000`	Handling and/or conveyance of specimen (non-covered code; example)	Administrative or specimen handling charges sometimes billed in the workflow when additional handling is required.