Coding Ahead
CasePilot
Medical Coding Assistant
Case2Code
Search and Code Lookup Tool
CareerCenter
Medical Coding Job Board
Log in Register free account

Need help choosing the right code?

Ask CasePilot about procedures, modifiers, bundling, and coding guidance.

Try CasePilot

Official Description

Insulin; free

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Insulin is a crucial hormone produced by the pancreas that plays a vital role in the regulation of blood glucose levels. It facilitates the utilization of circulating glucose for energy, while also promoting the storage of excess glucose as glycogen in liver and muscle cells. The measurement of insulin levels in the blood is essential for assessing various metabolic conditions, particularly diabetes. The CPT® Code 83527 specifically refers to the testing of free insulin levels in the bloodstream. This test is typically performed on a blood sample obtained through venipuncture, which is a procedure where a needle is inserted into a vein to collect blood. The specimen for this test can be collected at random or at specific timed intervals, such as 30, 60, 90, or 120 minutes after a 75-gram glucose challenge, which is a test used to evaluate how well the body processes glucose. It is important to note that for accurate results, the patient should be fasting prior to the test. The analysis of the blood sample is conducted using quantitative ultrafiltration, a method that allows for the precise measurement of free insulin levels in serum or plasma.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The insulin free test (CPT® Code 83527) is indicated for the evaluation of various metabolic disorders, particularly in the context of diabetes management. The following conditions may warrant this test:

  • Diabetes Mellitus This condition is characterized by chronic high blood sugar levels due to insulin resistance or insufficient insulin production.
  • Insulinoma A rare tumor of the pancreas that produces excess insulin, leading to hypoglycemia.
  • Hypoglycemia Episodes of low blood sugar that may require investigation to determine the underlying cause, including inappropriate insulin secretion.
  • Evaluation of Insulin Sensitivity This test can help assess how effectively the body responds to insulin, which is crucial for managing conditions like metabolic syndrome.

2. Procedure

The procedure for obtaining a blood sample for the insulin free test involves several key steps:

  • Step 1: Patient Preparation Prior to the test, the patient must be instructed to fast for a specified period, typically overnight, to ensure accurate measurement of free insulin levels. Fasting helps eliminate any immediate effects of food intake on insulin levels.
  • Step 2: Venipuncture A qualified healthcare professional will perform a venipuncture, which involves inserting a sterile needle into a vein, usually in the arm, to collect a blood sample. Proper aseptic technique is essential to minimize the risk of infection.
  • Step 3: Specimen Collection The blood sample is collected into a suitable container, typically a serum or plasma tube, which is then labeled appropriately for identification. The specimen may be taken at random or at timed intervals following a glucose challenge, depending on the clinical scenario.
  • Step 4: Laboratory Analysis The collected specimen is sent to a laboratory where it undergoes quantitative ultrafiltration to measure the free insulin levels. This method allows for the separation of free insulin from other components in the blood, providing an accurate assessment of insulin availability.

3. Post-Procedure

After the blood sample has been collected, there are generally no specific post-procedure care requirements for the patient. However, it is advisable for the patient to resume normal activities unless otherwise instructed by the healthcare provider. The results of the insulin free test will be analyzed and reported back to the physician, who will interpret the findings in the context of the patient's overall health and any symptoms they may be experiencing. Follow-up appointments may be necessary to discuss the results and any further diagnostic or therapeutic steps that may be required.

Short Descr ASSAY OF INSULIN
Medium Descr ASSAY OF INSULIN FREE
Long Descr Insulin; free
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
90 Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
91 Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient.
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
Date
Action
Notes
2013-01-01 Changed Medium Descriptor changed.
1994-01-01 Added First appearance in code book in 1994.
Code
Description
Code
Description
CasePilot

Get instant expert-level medical coding assistance.

Ask about:
CPT Codes Guidelines Modifiers Crosswalks NCCI Edits Compliance Medicare Coverage
Example: "What is CPT code 99213?" or "Guidelines for E/M services"