Summary & Overview
CPT 83664: Lamellar Body Density Test for Fetal Lung Maturity
CPT code 83664 represents a laboratory diagnostic assay — the lamellar body density test — used to assess fetal lung maturity and help determine whether the fetal respiratory system is likely to support extrauterine life. This test is clinically significant in perinatal decision-making, particularly when timing of delivery is being considered due to maternal or fetal indications.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise review of clinical context for the test, the typical site of service, and the common billing considerations associated with this laboratory service.
The publication provides benchmarks and policy-relevant content: national utilization context for fetal lung maturity testing, payer coverage themes and common coding practices, and high-level notes on sites of service where 83664 is performed. It also includes clinical context explaining why lamellar body density is measured and how results inform obstetric management. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 83664 describes a lamellar body density test performed by a laboratory analyst to assess fetal lung maturity. The test evaluates the maturity of fetal lungs as an indication of whether the organ system will be able to support life outside the uterus.
Service Type: Laboratory diagnostic test for fetal lung maturity
Typical Site of Service: Clinical laboratory or hospital laboratory setting. If performed as part of perinatal care, the specimen is usually collected in an outpatient obstetrics clinic or inpatient maternity unit and processed in a laboratory.
Clinical & Coding Specifications
Clinical Context
A typical patient is a pregnant person in the late second or third trimester being evaluated for fetal lung maturity when there is concern about the timing of delivery. Indications include preterm labor, preeclampsia with possible early delivery, maternal medical conditions requiring delivery (e.g., poorly controlled diabetes), or obstetric complications that may warrant induction or cesarean before term. The clinical workflow begins with the obstetrician ordering a fetal lung maturity assessment. A specimen of amniotic fluid is obtained via amniocentesis or collected at the time of rupture of membranes. The specimen is sent to the clinical laboratory labeled with patient identifiers, ordering provider, and relevant clinical information. In the laboratory, a trained medical technologist or laboratory analyst performs the lamellar body count or lamellar body density test (83664) to assess surfactant content as a proxy for pulmonary maturity. Results are reported back to the obstetric team, who integrate the finding with gestational age, fetal status, and maternal condition to inform timing of delivery. Typical site of service is the hospital labor and delivery unit or an outpatient hospital-based obstetric clinic with access to an on-site clinical laboratory. Specimens may also be processed in a reference laboratory. Typical patient scenario: a 34-week gestation patient with worsening preeclampsia where the clinician must decide whether to proceed with delivery; amniocentesis is performed and 83664 is ordered to evaluate fetal lung maturity prior to delivery planning.
Coding Specifications
| Modifier | Description | When to Use |
|---|