CPT 0432U: Kelch–Like Protein 11 Antibody Test (Mayo Clinic)

CPT code 0432U designates a Proprietary Laboratory Analyses (PLA) test for Kelch–Like Protein 11 (KLHL11) Antibody performed by Mayo Clinic/Mayo Clinic Laboratories. The test, performed by a cell binding assay on cerebrospinal fluid or serum, identifies a biomarker linked to autoimmune and neoplasm‑associated encephalitis. As a PLA code, 0432U is specific to a single manufacturer or laboratory and signals unique clinical and billing considerations for specialty antibody testing.

Key national payers referenced include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The code is relevant to neurologists, oncologists, clinical laboratories, and payers handling specialty diagnostic claims for encephalitis workups.

Readers will find clinical context on the test’s purpose and sample types, an overview of payer coverage landscape, and practical billing considerations specific to PLA coding. The publication outlines common modifiers used with laboratory services, typical sites of service, and what is and is not available in the input data. It focuses on national implications for access to targeted antibody testing and administrative handling of a single‑source proprietary assay.

Billing Code Overview

CPT code 0432U is a Proprietary Laboratory Analyses (PLA) code that applies exclusively to a single proprietary test: Kelch–Like Protein 11 Antibody performed by Mayo Clinic/Mayo Clinic Laboratories. The assay uses a cell binding assay method to evaluate a cerebrospinal fluid (CSF) or serum specimen for the presence of KLHL11 Antibody, a biomarker associated with autoimmune or neoplasm–associated encephalitis.

Service Type: Laboratory — Proprietary serologic/CSF antibody testing

Typical Site of Service: Clinical laboratory or reference laboratory setting, with specimens collected in outpatient clinics, hospitals, or inpatient facilities

Data not available in the input.

Clinical Context

A 54-year-old man presents to neurology with progressive cognitive decline, new-onset seizures, and subacute encephalopathy over several weeks. MRI brain shows T2 hyperintensities in the medial temporal lobes and cerebrospinal fluid (CSF) analysis demonstrates pleocytosis. The neurologist suspects autoimmune or paraneoplastic encephalitis and orders Kelch–Like Protein 11 Antibody testing from Mayo Clinic Laboratories. A CSF specimen is preferred; serum may be submitted if lumbar puncture is not performed. The specimen is collected, labeled, and shipped per Mayo’s instructions. Clinical workflow: neurology documents the suspected autoimmune/paraneoplastic encephalitis diagnosis in the chart, places the order in the electronic health record specifying Mayo Clinic Laboratories testing using the PLA test 0432U, obtains the specimen (CSF or serum) in the outpatient clinic, emergency department, or inpatient setting, completes required test requisition details, and sends the specimen to the reference lab. Results inform diagnosis of KLHL11-associated autoimmune or neoplasm–associated encephalitis and guide further oncologic evaluation and immunotherapy planning.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional interpretation component of a separate diagnostic procedure associated with this test (rare for PLA).

Taxonomy Code	Specialty	Notes
2084P0800X	Neurology	Neurologists most commonly order KLHL11 antibody testing for suspected autoimmune encephalitis.
208000000X	Pathology	Clinical pathologists oversee laboratory testing quality and interpretation coordination with reference labs.
207P00000X	Psychiatry & Neurology (combined)	Neuropsychiatrists may evaluate cognitive/behavioral presentations prompting testing.
207L00000X	Internal Medicine	Hospitalists or internists may order testing during inpatient evaluation of altered mental status.
363A00000X	Emergency Medicine	Emergency physicians may order initial testing when patients present with acute encephalopathy or seizures.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`G04.81`	Autoimmune encephalitis	Direct indication for ordering KLHL11 antibody testing to identify autoimmune-mediated encephalitis.
`G04.89`	Other encephalitis, myelitis and encephalomyelitis	Used when encephalitic processes are suspected but not yet specified; KLHL11 testing helps narrow etiology.
`G40.909`	Epilepsy, unspecified, not intractable, without status epilepticus	Seizures are a common presenting feature prompting CSF/serum autoimmune antibody testing.
`R41.3`	Other amnesia	New memory loss may prompt evaluation for limbic encephalitis including KLHL11 antibody testing.
`C80.9`	Malignant neoplasm, unspecified	Paraneoplastic associations warrant KLHL11 testing when an occult tumor is suspected as the trigger.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`0432U`	Kelch–Like Protein 11 Antibody, Mayo Clinic Laboratories (PLA)	The specific Proprietary Laboratory Analysis code for KLHL11 antibody testing performed by Mayo Clinic; used to report the definitive antibody assay on CSF or serum.
`87070`	Culture, bacterial; aerobic, with isolation and presumptive identification of isolates	May be ordered earlier in the workflow to exclude infectious causes of encephalitis prior to autoimmune antibody results.
`88112`	Cytopathology, fluid, except cervical or urine, initial interpretation	Applied when CSF cytology is performed to evaluate for malignant cells in suspected paraneoplastic syndromes.
`88342`	Immunohistochemistry or immunocytochemistry, per single antibody stain	May be used when tissue immunostaining is performed to help identify an underlying neoplasm that could be associated with KLHL11 antibodies.
`82784`	Adenosine deaminase (ADA), serum or plasma	Occasionally ordered in CSF panels to evaluate differential causes of CNS inflammation; adjunctive to autoimmune testing.

OpenPayer

Summary & Overview