Summary & Overview
CPT 84132: Assay of Serum Potassium
CPT code 84132 is a widely utilized laboratory procedure for the assay of serum potassium, a key indicator of electrolyte balance in patients. This test is fundamental in the diagnosis and management of conditions such as hyperkalemia, hypokalemia, hypertension, and chronic kidney disease. The code is recognized and reimbursed by major national payers, including Aetna, Blue Cross Blue Shield, Cigna Health, and UnitedHealthcare, underscoring its importance in both clinical and billing contexts.
This publication provides a comprehensive overview of CPT code 84132, detailing its clinical relevance, typical sites of service, and payer coverage. Readers will gain insights into current benchmarks, policy updates, and the broader clinical context for serum potassium testing. The analysis also highlights associated modifiers, relevant taxonomies, and common ICD-10 diagnoses linked to this laboratory service. By understanding the nuances of this code, stakeholders can better navigate the evolving landscape of laboratory billing and reimbursement.
CPT Code Overview
CPT code 84132 represents the assay of serum potassium, a critical chemistry laboratory test used to measure potassium levels in a patient's blood. This test is essential for monitoring electrolyte balance and is commonly performed in laboratory settings, including hospital laboratories and independent labs. Accurate assessment of serum potassium is vital for diagnosing and managing a range of medical conditions, making this procedure a cornerstone in clinical laboratory services.
Clinical & Coding Specifications
Clinical Context
A patient presents to a clinic or hospital with symptoms such as muscle weakness, fatigue, or irregular heart rhythms. The provider suspects an electrolyte imbalance and orders a chemistry laboratory test to measure serum potassium levels. The blood sample is collected and sent to a laboratory, which may be either within the hospital or an independent facility. The laboratory performs the assay using CPT code 84132 to determine the patient's potassium concentration. Results are used to diagnose or monitor conditions such as hyperkalemia, hypokalemia, hypertension, or chronic kidney disease.
Coding Specifications
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Modifiers:
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Modifier
90: Reference (Outside) Laboratory — Used when the laboratory test is performed by an outside laboratory rather than the facility where the specimen was collected. -
Modifier
91: Repeat Clinical Diagnostic Laboratory Test — Used when the same laboratory test is repeated on the same patient on the same day to obtain additional information.
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Provider Taxonomies:
| Taxonomy Code | Specialty Name |
|---|---|
291U00000X | Clinical Medical Laboratory |
207Q00000X | Family Medicine Physician |
207R00000X | Internal Medicine Physician |
Related Diagnoses
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E87.5— Hyperkalemia- Relevant for patients with elevated serum potassium levels; the assay helps confirm and monitor this condition.
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E87.6— Hypokalemia- Used for patients suspected of having low serum potassium; the test is essential for diagnosis and management.
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R79.89— Other specified abnormal findings of blood chemistry- Applied when abnormal potassium results are found that do not fit specific diagnoses; supports further investigation.
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I10— Essential (primary) hypertension- Potassium levels may be monitored in hypertensive patients, especially when on medications affecting electrolytes.
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N18.9— Chronic kidney disease, unspecified- Kidney disease often affects potassium regulation; the assay is important for ongoing assessment in these patients.
Related CPT Codes
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80047— Basic Metabolic Panel (Calcium, ionized) — includes potassium- This panel includes the measurement of serum potassium along with other electrolytes and calcium. It is commonly ordered when a broader assessment of a patient's metabolic status is needed. In clinical workflow,
80047may be used as an alternative to84132when multiple analytes are required, or together if a specific potassium assay is needed in addition to the panel.
- This panel includes the measurement of serum potassium along with other electrolytes and calcium. It is commonly ordered when a broader assessment of a patient's metabolic status is needed. In clinical workflow,
National Reimbursement Benchmarks
For CPT code 84132, the national mean rate for BUCA (average commercial) is $5.67, which is higher than the typical Medicare rate for similar laboratory codes, though Medicare data is not available in the input for direct comparison. Among individual commercial payers, Cigna has the highest mean rate at $7.41, while UnitedHealth Group is lowest at $4.13.
Rate dispersion, measured by the difference between the 75th and 25th percentiles, varies across payers. Cigna shows the widest spread ($7.00 - $3.50 = $3.50), indicating greater variability in contracted rates. UnitedHealth Group has the tightest range ($4.33 - $2.00 = $2.33), suggesting more consistent rates nationally. Aetna and Blue Cross Blue Shield fall in between, with ranges of $2.75 and $1.82, respectively.
The table and chart below present a full breakdown of national mean rates and percentile distributions for each payer.
Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.