Summary & Overview
CPT 83935: Urine Osmolality Measurement
CPT code 83935 represents a laboratory measurement of urine osmolality, a clinical test that quantifies dissolved particles in urine to assess concentration and renal concentrating ability. Nationally, urine osmolality testing is used in the evaluation of fluid and electrolyte disorders, diabetes insipidus, syndrome of inappropriate antidiuretic hormone (SIADH), and monitoring of renal function. Its measurement informs clinical decision-making for inpatient and outpatient care and is commonly billed by hospital and independent clinical laboratories.
Key payers commonly involved in coverage and reimbursement for this service include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides a concise review of code placement in the CPT system, clinical context for test ordering, and the typical sites where the service is performed. Readers will find an explanation of the test’s clinical purpose, common billing modifiers supplied in the input, and an outline of where to expect this service on a claim.
The analysis offers practical reference material for administrators, lab managers, and billing staff: a clinical summary of the procedure, coding context, and operational considerations for laboratories that perform urine osmolality testing. Data not available in the input: specific reimbursement benchmarks, payer-specific policy details, associated taxonomies, ICD-10 diagnoses, related codes, and service line assignment.
Billing Code Overview
CPT code 83935 measures urine osmolality, a laboratory test that quantifies the number of dissolved particles in a urine specimen. The test is most commonly performed on a random urine sample and assesses solute concentration by evaluating effects such as increased boiling point and decreased freezing point.
-
Service type: Clinical laboratory test — urine osmolality measurement
-
Typical site of service: Clinical laboratory or hospital laboratory; specimen collected in outpatient clinics, inpatient settings, or at point-of-care collection sites
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult presenting to an outpatient clinic or emergency department with symptoms of abnormal fluid balance such as polyuria, polydipsia, dizziness, orthostatic symptoms, or suspected acute kidney injury. A provider orders a urine osmolality test to assess urine concentrating ability and help distinguish causes of hyponatremia, diabetes insipidus, syndrome of inappropriate antidiuretic hormone secretion (SIADH), or dehydration. A random or spot urine specimen is collected in the clinic, ED, or sent from inpatient wards to the clinical laboratory. The laboratory analyst performs 83935 using an osmometer; results are reported to the ordering clinician and incorporated into the diagnostic workup alongside serum osmolality, basic metabolic panel, and relevant endocrine or nephrology consult notes. Typical sites of service include outpatient clinic, emergency department, inpatient hospital laboratory, and independent clinical laboratory facilities.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation component (rare for 83935, typically lab-only). |