Need help choosing the right code?
Ask CasePilot about procedures, modifiers, bundling, and coding guidance.
Try CasePilot© Copyright 2026 American Medical Association. All rights reserved.
The CPT® Code 84305 refers to a laboratory test specifically designed to measure the levels of somatomedin, also known as Insulin-Like Growth Factor-1 (IGF1). This test is significant in the field of endocrinology as it provides valuable insights into the growth hormone (hGh) activity within the body. Somatomedin is primarily produced by liver and muscle cells and acts as a crucial growth factor that is stimulated by somatotropin, which is the human growth hormone. The measurement of IGF1 is particularly useful because, unlike somatotropin levels that fluctuate throughout the day, IGF1 levels remain relatively constant, making it a reliable marker for evaluating the production of hGh by the pituitary gland. The clinical implications of somatomedin testing are substantial. Low levels of IGF1 may suggest conditions such as malnutrition, short stature, or delayed puberty, indicating a potential deficiency in growth hormone production. Conversely, elevated levels of IGF1 can be associated with conditions like gigantism, which is characterized by excessive growth due to overproduction of growth hormone. The test is performed by obtaining a blood sample through venipuncture, which is a separately reportable procedure. The serum obtained from the blood sample is then analyzed using a quantitative chemiluminescent immunoassay, a sensitive and specific method for measuring IGF1 levels in the laboratory.
© Copyright 2026 Coding Ahead. All rights reserved.
The somatomedin (IGF1) test, represented by CPT® Code 84305, is indicated for various clinical scenarios where assessment of growth hormone activity is necessary. The following conditions may warrant this test:
The procedure for obtaining a somatomedin (IGF1) test involves several key steps that ensure accurate measurement of the hormone levels. The following procedural steps are outlined:
After the procedure, the patient may experience minor discomfort or bruising at the venipuncture site, which typically resolves quickly. There are no specific post-procedure care instructions required for the IGF1 test, but patients should be advised to hydrate adequately and report any unusual symptoms to their healthcare provider. The results of the test will be analyzed and interpreted by a qualified healthcare professional, who will discuss the findings with the patient and determine any necessary follow-up actions based on the IGF1 levels measured.
| Short Descr | ASSAY OF SOMATOMEDIN | Medium Descr | ASSAY OF SOMATOMEDIN | Long Descr | Somatomedin | 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. | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | 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 | 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. | GZ | Item or service expected to be denied as not reasonable and necessary | 77 | Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service. | 95 | Synchronous telemedicine service rendered via a real-time interactive audio and video telecommunications system: synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that would be sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. modifier 95 may only be appended to the services listed in appendix p. appendix p is the list of cpt codes for services that are typically performed face-to-face, but may be rendered via a real-time (synchronous) interactive audio and video telecommunications system. | GA | Waiver of liability statement issued as required by payer policy, individual case | GV | Attending physician not employed or paid under arrangement by the patient's hospice provider | GW | Service not related to the hospice patient's terminal condition | Q4 | Service for ordering/referring physician qualifies as a service exemption |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2013-01-01 | Changed | Medium Descriptor changed. |
| 1993-01-01 | Added | First appearance in code book in 1993. |
Get instant expert-level medical coding assistance.