Summary & Overview

CPT 88140: Peripheral Blood Smear for Sex Chromatin Identification

CPT code 88140 designates a laboratory test in which a trained analyst examines a peripheral blood smear to identify polymorphonuclear "drumstick" nuclear protrusions for sex chromatin (Barr body) identification. This microscopic technical service supports clinical and forensic determinations of chromatin patterns and can inform downstream genetic or diagnostic workflows. Nationally, the code matters because it defines billing for a specialized morphologic laboratory procedure that has implications for clinical documentation, lab capacity, and reimbursement consistency across payers.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical context for the test, typical sites of service, and the service type captured by the code. The publication also outlines common billing modifiers (provided separately), and highlights areas where data was provided versus where input was not available.

This summary equips laboratory managers, clinical billers, and policy analysts with a clear, national-level reference for CPT code 88140, including what the code represents, why it is used, and what to expect in terms of clinical application and billing classification. Data not available in the input.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare88140CPTperipheral blood smearsex chromatinlaboratorymicroscopypathologyhematology

Billing Code Overview

CPT code 88140 describes a laboratory technical service that analyzes a peripheral blood smear to identify polymorphonuclear drumsticks used for sex chromatin identification. The procedure involves preparing and microscopically examining a peripheral blood smear to detect characteristic drumstick-shaped nuclear protrusions representing a coiled female X chromosome in polymorphonuclear leukocytes.

Service Type: Laboratory — microscopic peripheral blood smear analysis for sex chromatin identification

Typical Site of Service: Clinical laboratory or hospital laboratory, where trained laboratory analysts perform microscopic evaluation of blood smears.

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 28-year-old individual assigned female at birth presents to an outpatient hematology laboratory after a primary care provider orders sex chromatin testing to help clarify unexpected karyotype findings from prior prenatal screening or to evaluate disorders of sexual development. The patient has a recent complete blood count with differential and a peripheral blood smear obtained by venipuncture. The laboratory technologist prepares and stains the peripheral smear (e.g., Wright-Giemsa) and the lab analyst performs a microscopic evaluation to identify polymorphonuclear "drumstick" nuclear appendages (Barr bodies) for sex chromatin identification. Results are reported to the ordering clinician and incorporated into the patient’s chart. Typical site of service is an outpatient clinical laboratory or hospital laboratory under physician or clinical laboratory director oversight. Specimen handling, staining, microscopic examination, interpretation, and reporting follow institutional laboratory protocols and CLIA regulations.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional (interpretive) portion if the lab separates technical and professional components and the physician/pathologist provides the interpretive report.
`TC`	Technical component	Use when billing only the technical component for specimen processing, staining, and microscopy when no professional interpretation is billed.
`90`	Reference (outside) laboratory	Use when the test was performed by an outside reference laboratory and the billing facility is reporting that fact.
`52`	Reduced services	Use when the test was partially performed or limited in scope compared with the full procedure.
`53`	Discontinued procedure	Use when the test was started but discontinued for patient-related or technical reasons before completion.
`59`	Distinct procedural service	Data not available in the input.
`QK`	Qualified nonphysician laboratory director	Use when a qualified nonphysician laboratory director oversaw the testing in accordance with CLIA.
`QX`	Modifier under CLIA for personnel	Use when a clinical laboratory performed testing under a specific nonphysician personnel arrangement.
`QY`	Laboratory test performed by an independent laboratory	Use when the test was performed by an independent laboratory billing separately.
`90`	Reference (outside) laboratory	Data not available in the input.

Taxonomy Code	Specialty	Notes
207Q00000X	Clinical Pathology	Physicians/pathologists supervising clinical laboratory testing and interpretation.
207R00000X	Hematology	Physicians specializing in hematology who order and interpret peripheral smear evaluations.
163WP0800X	Medical Laboratory Technologist/Technician	Laboratory professionals who prepare and stain smears and perform technical microscopy.
2080P0204X	Pediatric Pathology	Pediatric pathologists may be involved when testing is ordered for congenital or developmental concerns.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`Z87.890`	Personal history of sex chromosome abnormality	Relevant when assessing prior documented sex chromosome anomalies where sex chromatin testing may be used for confirmation or monitoring.
`Q98.8`	Other sex chromosome abnormalities	Applicable when sex chromatin testing is used as part of evaluating suspected chromosomal disorders.
`Q96.9`	Turner syndrome, unspecified	Peripheral smear sex chromatin may be part of the diagnostic evaluation or follow-up in suspected Turner syndrome cases.
`Q97.9`	Klinefelter syndrome, unspecified	Sex chromatin testing can be adjunctive when chromosomal abnormalities are suspected in individuals with relevant phenotypes.
`R79.9`	Abnormal finding of laboratory study, unspecified	Used when an abnormal lab result prompts additional testing such as sex chromatin identification.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`81001`	Urinalysis, by dip stick or tablet reagent for bilirubin, glucose, hemoglobin, ketones, leukocytes, nitrite, pH, specific gravity, etc., non-automated, with microscopy	Often performed in parallel during workup of systemic disorders affecting blood cells or sex chromosome anomalies when broader metabolic or renal screening is indicated.
`85025`	Blood count; complete (CBC) automated and automated differential WBC count	Frequently ordered before or with a peripheral smear to assess white cell morphology and counts that prompt smear review.
`85060`	Blood smear interpretation by a physician with written report	Performed when a physician issues a formal interpretive report after microscopic review, often billed in conjunction with the technical smear work.
`88232`	Analysis of tissue by cytogenetic technique, biopsy culture, etc.	Performed in cases requiring cytogenetic studies beyond smear sex chromatin identification, such as karyotyping or FISH.
`88271`	Microarray analysis, genomic copy number and single nucleotide polymorphism genome-wide; patient-level raw and interpreted data	Used when more detailed chromosomal analysis is required following abnormal sex chromatin findings.