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Official Description

Protein, total, except by refractometry; serum, plasma or whole blood

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 84155 refers to a laboratory test that measures the total protein levels in a sample of serum, plasma, or whole blood, excluding methods that utilize refractometry. This test is essential for assessing the overall protein content in the blood, which is crucial for various physiological functions. Total protein levels are typically reported alongside the albumin to globulin (A/G) ratio, providing insight into the balance between these two major protein types. In a healthy individual, albumin levels are generally slightly higher than globulin levels. The total protein test is instrumental in monitoring a patient's nutritional status and can aid in the diagnosis of several medical conditions, particularly those affecting the kidneys and liver. Elevated total protein levels may suggest the presence of chronic inflammation, viral infections such as hepatitis, HIV, or conditions like multiple myeloma. Conversely, decreased protein levels can indicate issues such as malnutrition or malabsorption syndromes, including celiac disease or inflammatory bowel disease. The test requires a blood sample, which is obtained through a venipuncture procedure that is reported separately. The analysis of the blood sample is performed using quantitative spectrophotometry, a method that quantifies the concentration of proteins in the sample.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The total protein test (CPT® Code 84155) is indicated for various clinical scenarios, particularly when assessing a patient's health status or diagnosing specific conditions. The following are the primary indications for performing this test:

  • Monitoring Nutritional Status This test is utilized to evaluate a patient's nutritional health, helping to identify potential deficiencies or imbalances in protein intake.
  • Diagnosing Kidney Disease Abnormal total protein levels can indicate kidney dysfunction, prompting further investigation into renal health.
  • Diagnosing Liver Disease The test aids in assessing liver function, as the liver is responsible for producing many proteins found in the blood.
  • Identifying Chronic Inflammation Elevated protein levels may suggest ongoing inflammation in the body, which can be associated with various chronic conditions.
  • Detecting Viral Infections Conditions such as viral hepatitis and HIV can lead to changes in total protein levels, making this test useful for diagnosis.
  • Evaluating Multiple Myeloma Increased total protein levels may indicate the presence of multiple myeloma, a type of blood cancer that affects plasma cells.
  • Assessing Malnutrition or Malabsorption Syndromes Decreased protein levels can signal malnutrition or conditions like celiac disease and inflammatory bowel disease, which affect nutrient absorption.

2. Procedure

The procedure for conducting the total protein test involves several key steps to ensure accurate results. The following outlines the procedural steps:

  • Step 1: Patient Preparation Prior to the test, the patient may be instructed to fast for a certain period, although specific fasting requirements can vary based on the healthcare provider's recommendations.
  • Step 2: Venipuncture A qualified healthcare professional performs a venipuncture to obtain a blood sample. This involves cleaning the skin at the puncture site, typically in the arm, and inserting a needle into a vein to draw blood into a collection tube.
  • Step 3: Sample Handling Once the blood sample is collected, it is properly labeled and handled according to laboratory protocols to prevent contamination or degradation of the sample.
  • Step 4: Laboratory Analysis The blood sample is then sent to a laboratory where it undergoes analysis using quantitative spectrophotometry. This method measures the concentration of total protein in the serum, plasma, or whole blood sample.
  • Step 5: Result Interpretation After analysis, the laboratory generates a report detailing the total protein levels and the A/G ratio, which is then reviewed by the healthcare provider for clinical interpretation.

3. Post-Procedure

After the total protein test is completed, there are generally no specific post-procedure care requirements for the patient. However, it is common for patients to experience minor discomfort or bruising at the venipuncture site, which typically resolves on its own. Patients are usually advised to resume normal activities immediately following the test. The healthcare provider will discuss the results with the patient during a follow-up appointment, where any necessary further evaluations or treatments will be determined based on the total protein levels and overall clinical context.

Short Descr ASSAY OF PROTEIN SERUM
Medium Descr PROTEIN XCPT REFRACTOMETRY SERUM PLASMA/WHL BLD
Long Descr Protein, total, except by refractometry; serum, plasma or whole blood
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) Yes
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.
QW Clia waived test
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.
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.
GA Waiver of liability statement issued as required by payer policy, individual case
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
GZ Item or service expected to be denied as not reasonable and necessary
GW Service not related to the hospice patient's terminal condition
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
KX Requirements specified in the medical policy have been met
Q4 Service for ordering/referring physician qualifies as a service exemption
X5 Diagnostic services requested by another clinician: for reporting services by a clinician who furnishes care to the patient only as requested by another clinician or subsequent and related services requested by another clinician; this modifier is reported for patient relationships that may not be adequately captured by the above alternative categories; reporting clinician service examples include but are not limited to, the radiologist's interpretation of an imaging study requested by another clinician
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.
AY Item or service furnished to an esrd patient that is not for the treatment of esrd
CR Catastrophe/disaster related
GC This service has been performed in part by a resident under the direction of a teaching physician
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
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
Q3 Live kidney donor surgery and related services
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
QJ Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b)
XE Separate encounter, a service that is distinct because it occurred during a separate encounter
Date
Action
Notes
2011-01-01 Changed Short description changed.
2009-01-01 Changed Code description changed
2004-01-01 Changed Code description changed.
Pre-1990 Added Code added.
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Description
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