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    v1.0.28
    OpenPayerBilling CodesHematology and Coagulation ProceduresCPT cpt-85378-d-dimer-assay-blood-plasma
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    CPT 85378: D-dimer Assay in Blood or Plasma

    CPT code 85378 describes a laboratory immunoassay performed on patient blood or plasma to detect D‑dimer at clinically significant levels; this is a clinical pathology diagnostic test used to evaluate suspected thrombotic events, typically processed in a hospital laboratory or reference/clinical laboratory setting and reported as a discrete laboratory service.

    For related coverage guidance, see recent payer policy updates: Epithelial Cell Cytology in Breast Cancer Risk Assessment, Chemotherapy Observation or Inpatient Hospitalization (for New Mexico Only), Antibody-Drug Conjugates.

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    Table of contents

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    Clinical & Coding Specifications

    Clinical Context

    A 58-year-old woman presents to the emergency department with acute-onset unilateral leg swelling and pleuritic chest pain. The emergency physician obtains a focused history and performs vitals, then orders laboratory testing to evaluate for venous thromboembolism. A blood sample is collected and sent to the hospital clinical laboratory for a quantitative D‑dimer assay (85378) to determine whether fibrin degradation products are present at clinically significant levels. The laboratory technologist performs the assay on plasma using an immunoassay platform and reports a numeric D‑dimer value with the lab result. Results are routed to the ordering clinician; an elevated D‑dimer in this clinical context supports further diagnostic imaging (for example, duplex ultrasound of the leg or CT pulmonary angiography), while a normal D‑dimer may support ruling out acute pulmonary embolism or deep vein thrombosis in patients with low pretest probability.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    36415Collection of venous blood by venipunctureBlood specimen collection performed immediately prior to 85378.
    73721Magnetic resonance (MR) angiography, any joint, without contrast (example placeholder)Data not available in the input.
    71260CT angiography, chest, with contrast material (used for pulmonary embolism evaluation)Often performed after an elevated 85378 when clinical suspicion for pulmonary embolism remains.
    93970Duplex scan of extremity veins, complete bilateral studyPerformed after a positive D‑dimer to evaluate for deep vein thrombosis.
    36416Collection of capillary blood specimen (finger/heel)Alternative specimen collection method when venipuncture is not feasible prior to 85378.

    Related Modifiers

    6 rows

    ModifierDescriptionWhen to Use
    26Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…
    90Modifier ‑90 (Reference/Outside Laboratory) indicates that a laboratory test was performed by an entity other than the treating or reporting provider. The American Medical Association defines…- Use CPT modifier -90 when a laboratory test is performed by an outside/reference laboratory (an entity other than the treating or reporting physician or qualified professional) and the claim needs…
    91Modifier 91 — “Repeat Clinical Diagnostic Laboratory Test” — is appended when the exact same CPT laboratory test is performed more than once for the same patient on the same day because serial,…- Use modifier 91 when the exact same CPT laboratory test is performed more than once on the same patient on the same date because serial or repeated testing is medically necessary to monitor…
    52Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
    53Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
    59Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    207RG0100XGastroenterology PhysicianAn internist who specializes in diagnosis and treatment of diseases of the digestive organs including the stomach, bowels, liver and gallbladder. This…
    207L00000XAnesthesiology PhysicianAn anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
    207P00000XEmergency Medicine PhysicianAn emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospit…
    2471B0102XBone Densitometry Radiologic TechnologistA radiologic technologist who specializes in bone densitometry and is appropriately educated and trained, consistent with nationally recognized standa…
    332BD1200XDialysis Equipment & Supplies (DME)Suppliers · Durable Medical Equipment & Medical Supplies
    2080P0202XPediatric Cardiology PhysicianA pediatric cardiologist provides comprehensive care to patients with cardiovascular problems. This specialist is skilled in selecting, performing and…
    1223P0106XOral and Maxillofacial Pathology DentistryThe specialty of dentistry and discipline of pathology that deals with the nature, identification, and management of diseases affecting the oral and m…
    163WH0200XHome Health Registered NurseNursing Service Providers · Registered Nurse

    Related Payer Policy Updates

    Specialty: Hematology/Oncology1 / 3

    4 rows

    PolicyPayerEffective Date
    Epithelial Cell Cytology in Breast Cancer Risk AssessmentOscar Health2026-10-01
    Chemotherapy Observation or Inpatient Hospitalization (for New Mexico Only)UnitedHealthcare2026-08-01
    Antibody-Drug ConjugatesPremera Bluecross2026-08-01
    Umbilical Cord Blood Harvesting and Storage for Future Use (for Indiana Only)UnitedHealthcare2026-08-01

    Related Codes

    CPT-85002-BLEEDING-TIME-TEST-LABORATORY

    CPT 85002: Bleeding Time Test, Technical Component

    CPT-85004-AUTOMATED-DIFFERENTIAL-WHITE-BLOOD-CELL-COUNT

    CPT 85004: Automated White Blood Cell Differential

    CPT-85007-MANUAL-DIFFERENTIAL-WHITE-BLOOD-CELL-COUNT

    CPT 85007: Manual Differential White Blood Cell Count

    CPT-85008-BLOOD-SMEAR-MORPHOLOGIC-REVIEW-NO-DIFFERENTIAL

    CPT 85008: Microscopic Blood Smear Examination, No Differential

    CPT-85009-MANUAL-WBC-COUNT-BUFFY-COAT

    CPT 85009: Manual White Blood Cell Count Using Buffy Coat

    CPT-85013-MICROHEMATOCRIT-TEST-LABORATORY-DIAGNOSTIC

    CPT 85013: Microhematocrit Test by Tube Centrifugation

    CPT-85014-HEMATOCRIT-VOLUME-PERCENT-RED-BLOOD-CELLS

    CPT 85014: Hematocrit (Volume Percent of Red Blood Cells)

    CPT-85018-HEMOGLOBIN-ASSAY-WHOLE-BLOOD

    CPT 85018: Hemoglobin Measurement in Whole Blood

    CPT-85025-COMPLETE-BLOOD-COUNT-CBC

    CPT 85025: Complete Blood Count (CBC)

    CPT-85027-COMPLETE-BLOOD-COUNT-HGB-HCT

    CPT 85027: Complete Blood Count with Hemoglobin and Hematocrit

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    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
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