Summary & Overview
CPT 0524U: sFlt‑1/PlGF Ratio Assay for Preeclampsia Diagnosis
CPT code 0524U designates a Proprietary Laboratory Analyses (PLA) test for the PreClaraTMRatio, quantifying the ratio of soluble fms–like tyrosine kinase-1 (sFlt–1) to placental growth factor (PlGF) via immunoassay. This CPT PLA code is specific to Thermo Fisher Scientific's PreClaraTMRatio assay and is used to aid in the diagnosis of preeclampsia by assessing biomarkers associated with placental vascular function. Nationally, the code matters because targeted biomarker assays for preeclampsia are increasingly used to stratify risk, inform clinical decision-making, and influence use of maternal-fetal monitoring resources.
Key payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical purpose of the test, payer coverage context, common billing modifiers, and operational considerations for specimen type and typical site of service. The publication also summarizes expected content areas such as benchmark billing practices, relevant policy or coverage trends for proprietary lab tests, and clinical context for interpretation of an sFlt‑1/PlGF ratio. Data not available in the input will be identified where applicable.
Billing Code Overview
CPT code 0524U is a Proprietary Laboratory Analyses (PLA) code assigned specifically to the PreClaraTMRatio (sFlt–1/PlGF) test from Thermo Fisher Scientific. The assay measures the ratio of soluble fms–like tyrosine kinase-1 (sFlt-1) to placental growth factor (PlGF) using an immunoassay on a serum or plasma sample to aid in the diagnosis of preeclampsia.
Service type: Proprietary laboratory diagnostic immunoassay
Typical site of service: Clinical laboratory or hospital laboratory
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A pregnant patient in the second or third trimester presents to an obstetric clinic or hospital with new-onset hypertension, proteinuria, or symptoms concerning for preeclampsia such as severe headache, visual changes, epigastric pain, or rapid edema. The ordering clinician (maternal-fetal medicine specialist, obstetrician-gynecologist, or labor and delivery physician) requests the PreClaraTMRatio (sFlt–1/PlGF) immunoassay to aid in the diagnostic evaluation and short-term risk stratification for preeclampsia.
The clinical workflow: the patient undergoes venipuncture for serum or plasma collection in an outpatient clinic, antepartum testing unit, emergency department, or inpatient labor and delivery unit. The specimen is labeled and sent to the performing laboratory (or the manufacturer's designated lab) for analysis using the proprietary Thermo Fisher Scientific assay. Results are reported to the ordering clinician and incorporated into clinical decision-making regarding monitoring intensity, timing of delivery, need for transfer to a higher level of maternal-fetal care, or outpatient follow-up. Billing for this proprietary laboratory analysis is reported using 0524U for the specific PreClaraTMRatio test.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — standard reporting | Use when no additional modifier applies to the professional or technical components. |
26 | Professional component | Use when reporting only the professional component (interpretation) by the performing physician or laboratory director. |
TC | Technical component | Use when reporting only the technical component (laboratory processing, equipment, and supplies). |
52 | Reduced services | Use when the laboratory performed a partially reduced service compared with the full assay (rare for PLA tests). |
53 | Discontinued procedure | Use if specimen collection or testing was started but discontinued for documented clinical reasons. |
22 | Increased procedural services | Use when work or resources for test performance/reporting substantially exceed typical; must be well documented. |
90 | Reference (outside) laboratory | Use when the test was performed by an outside reference laboratory and only the ordering facility bills for the test. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207Q00000X | Maternal and Fetal Medicine (Perinatology) | Specialists who manage high-risk pregnancies and commonly order preeclampsia risk testing. |
| 207L00000X | Obstetrics & Gynecology | Obstetricians who evaluate and manage prenatal patients and order diagnostic testing. |
| 208D00000X | Emergency Medicine | Emergency physicians may order the assay when pregnant patients present with acute symptoms suggestive of preeclampsia. |
| 3336C0005X | Clinical Laboratory | Laboratory specialists who perform and validate the proprietary immunoassay. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
O14.03 | Mild pre-eclampsia, third trimester | Direct indication for sFlt-1/PlGF testing to aid diagnosis and risk stratification. |
O14.13 | Severe pre-eclampsia, third trimester | Used when assessing severity and short-term risk of progression; assay results inform monitoring/delivery decisions. |
O14.92 | Pre-eclampsia, unspecified, postpartum | Applied if preeclampsia is suspected or persistent after delivery; assay may be used in select postpartum evaluations. |
O13.9 | Gestational (pregnancy-induced) hypertension without significant proteinuria, unspecified trimester | sFlt-1/PlGF can help distinguish true preeclampsia from gestational hypertension. |
O99.89 | Other specified diseases and conditions complicating pregnancy, childbirth and the puerperium | May be used for related hypertensive or vascular disorders in pregnancy where biomarker testing assists diagnosis. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
80048 | Basic metabolic panel | Used to evaluate renal function and electrolytes in patients with suspected preeclampsia; commonly ordered alongside sFlt-1/PlGF testing. |
82043 | Assay of estriol, unconjugated | Data not directly related; included as an example of pregnancy-related serum assays — not routinely paired with sFlt-1/PlGF. |
81025 | Urine pregnancy test, qualitative | Performed earlier in pregnancy; not typically concurrent but part of obstetric workflow. |
99000 | Handling and/or conveyance of specimen | May be used by some facilities for specimen handling fees when applicable to specialized reference testing. |
99070 | Supplies and materials (e.g., sterile trays) | Used when additional supplies are used in the collection or processing of specimens for specialized assays. |