Summary & Overview
CPT 83704: Lipoprotein Particle Number and Subclass Assay
CPT code 83704 represents a laboratory assay that measures lipoprotein particle numbers and, when performed, particle subclasses in blood. This assay is clinically relevant because particle number can offer additional cardiovascular risk information beyond traditional lipid panels, influencing diagnostic evaluation and management pathways at a national level. The code is used for reporting specialized laboratory services performed in clinical or hospital laboratories.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of what CPT code 83704 covers, typical sites of service, and the clinical context for ordering the test. The publication outlines reimbursement and billing benchmarks, common billing scenarios, allowable modifiers listed for this code, and payer coverage patterns where available. It also summarizes policy considerations and documentation points relevant to labs and billing professionals.
The article is intended to inform laboratory managers, billing staff, clinicians ordering advanced lipid testing, and policy analysts about the code’s clinical role, billing context, and payer landscape on a national scale. Data not available in the input is noted explicitly where applicable.
Billing Code Overview
CPT code 83704 describes a laboratory test in which a lab analyst measures lipoprotein particle numbers and, when performed, lipoprotein particle subclasses in a blood specimen. This test quantifies the concentration of lipoprotein particles (for example, LDL particle number) to provide information beyond standard lipid panels.
Service Type: Clinical laboratory diagnostic test
Typical Site of Service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is a middle-aged adult referred by a primary care clinician or cardiologist for advanced lipid testing after persistently abnormal standard lipid panels or when residual cardiovascular risk is suspected despite statin therapy. The patient presents to an outpatient phlebotomy clinic attached to a hospital laboratory or an independent clinical laboratory. The clinical workflow: the ordering provider documents indications such as familial hypercholesterolemia, premature coronary artery disease, metabolic syndrome, or discordant LDL-C and clinical risk. A laboratory requisition for 83704 is received; patient identification and fasting status are confirmed if required; a venous blood specimen is collected and labeled; the specimen is processed and shipped or analyzed on site using nuclear magnetic resonance (NMR) spectroscopy or another validated assay to quantify lipoprotein particle numbers and subclasses. Results are reported to the ordering provider with particle concentrations (e.g., LDL-P, HDL-P) to assist in risk stratification and therapeutic decisions.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when only the professional interpretation/reporting portion is billed separate from the technical component. |
TC | Technical component | Use when billing only the technical component (laboratory processing and instrument) for the test. |
90 | Reference (outside) laboratory | Use when the specimen is sent to an outside laboratory and the submitting laboratory bills for the test performed by another lab. |
91 | Repeat clinical diagnostic laboratory test | Use when repeat testing on the same date is necessary to obtain accurate results. |
52 | Reduced services | Use when the test is partially performed or limited relative to the full service. |
53 | Discontinued procedure | Use when specimen collection or testing was started but discontinued due to patient condition or specimen issue. |
59 | Distinct procedural service | Use when another distinct laboratory service/procedure is performed on the same day and should be identified as separate. |
90 | Reference (outside) laboratory | Use when the performing lab is a reference lab (note: included for clarity when billing relationships require it). |
22 | Increased procedural services | Use when the laboratory documents unusually high complexity or time for processing beyond typical expectations. |
90 | Reference (outside) laboratory | Use when results or performance come from a separate contracted reference lab. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RH0000X | Clinical Pathology | Pathologists oversee laboratory testing, validation, and interpretation. |
| 207RP1001X | Clinical Laboratory | Laboratory medicine professionals who perform and validate assays. |
| 207RC0000X | Hematopathology | Specialists involved when specialized particle analysis impacts hematologic interpretation. |
| 207RE0101X | Chemical Pathology | Clinical chemists responsible for analytic methods such as NMR spectroscopy. |
| 208000000X | Cardiology | Ordering clinicians who request advanced lipid particle testing for cardiovascular risk management. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
E78.0 | Pure hypercholesterolemia | Elevated LDL particle numbers may be present; 83704 quantifies particle concentration for risk assessment. |
E78.5 | Hyperlipidemia, unspecified | Used when abnormal lipids prompt advanced particle testing to refine risk and treatment plans. |
E78.01 | Familial hypercholesterolemia (heterozygous) | Genetic dyslipidemia where lipoprotein particle numbers guide intensity of therapy. |
I25.10 | Atherosclerotic heart disease of native coronary artery without angina pectoris | Patients with known coronary artery disease may have particle testing to evaluate residual risk. |
E78.2 | Mixed hyperlipidemia | Complex lipid disorders frequently warrant particle subclass analysis to characterize atherogenic profile. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
80061 | Lipid panel; total cholesterol, HDL, and triglycerides (may include calculation of LDL-C) | Performed as the initial screening test; 83704 is ordered when particle number analysis is needed beyond standard lipid panel results. |
83721 | Apolipoprotein B (Apo B) measurement | Another advanced lipid biomarker often ordered alongside particle number testing to quantify atherogenic particle burden. |
83036 | Hemoglobin; glycated (A1c) | Commonly ordered in the same risk assessment profile for metabolic syndrome and cardiovascular risk evaluation. |
84478 | Testosterone; free or total (when relevant) | Occasionally ordered in broader endocrine workups associated with cardiometabolic risk; may be part of the same panel of tests. |
36415 | Collection of venous blood by venipuncture | The specimen collection procedure required before performing 83704. |