Test Id : USTEK
Ustekinumab Quantitation with Antibodies, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Evaluation of loss of response to therapy
Quantification of ustekinumab in human serum
Trough level quantitation for evaluation of patients treated with ustekinumab
Detection of antibodies to ustekinumab in human serum
Profile Information
A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
| Test Id | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| USQN | Ustekinumab QN, S | No | Yes |
| USTAB | Ustekinumab Ab, S | No | Yes |
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Ulcerative Colitis and Crohn Disease Therapeutic Drug Monitoring Algorithm.
Method Name
A short description of the method used to perform the test
Enzyme-Linked Immunosorbent Assay (ELISA)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Stelara
Stelara antibodies
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Ulcerative Colitis and Crohn Disease Therapeutic Drug Monitoring Algorithm.
Specimen Type
Describes the specimen type validated for testing
Serum
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Draw blood immediately before the next dose of drug administration (trough level).
2. Centrifuge and aliquot serum into a plastic vial.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send 1 of the following with the specimen:
-Gastroenterology and Hepatology Test Request (T728)
-Therapeutics Test Request (T831)
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.35 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
| Heat-inactivated specimen | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Evaluation of loss of response to therapy
Quantification of ustekinumab in human serum
Trough level quantitation for evaluation of patients treated with ustekinumab
Detection of antibodies to ustekinumab in human serum
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Ulcerative Colitis and Crohn Disease Therapeutic Drug Monitoring Algorithm.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Ustekinumab (UTK) is a fully human IgG1 kappa monoclonal antibody (1) that binds with high affinity to the p40 subunit of human interleukin (IL)12 and IL23 and has been approved for the treatment of patients with moderate to severe Crohn disease (CD), moderate to severe ulcerative colitis (UC), psoriatic arthritis, and plaque psoriasis. The drug prevents IL12 and IL23 bioactivity by binding and neutralizing the shared p40 subunit, preventing interaction with the cell surface receptor protein IL12Rbeta1. Through this mechanism of action, UTK effectively neutralizes IL12 and IL23, proteins that are thought to be associated with gastrointestinal inflammation in CD and UC. In the setting of the inflammatory bowel diseases (IBD), CD and UC, the treatment regimen is started with a single weight-based loading dose of the t-mab administered intravenously (IV), and a maintenance regimen with standard (non-weight based) subcutaneous administration of ustekinumab 8 weeks after induction dose, and every 8 weeks thereafter. There is very little data supporting proactive therapeutic drug monitoring for ustekinumab.
This test is most useful in the evaluation of loss of response to therapy. A gradual decrease in efficacy over time following an initial response to biologics is common. In many cases, antibodies generated to the biologic are responsible for treatment failure, as they bind to the drug creating an immunocomplex and clear the drug faster from circulation.
For IBD, measurements in nonresponders are indicated at post-induction (week 8) and concentrations of ustekinumab associated with favorable outcomes are greater than 3.5 mcg/mL. In addition, for measurements during maintenance stages of therapy, ustekinumab concentrations greater than or equal to 1 mcg/mL are associated with clinical response and clinical remission. At maintenance stages, ustekinumab concentrations greater than or equal to 4.5 mcg/mL are associated with mucosal healing.
In clinical trials, 6% to 12.4% of patients using ustekinumab for psoriasis or psoriatic arthritis developed antibodies-to-ustekinumab (ATU) over time. For IBD, between 2.9% and 4.6% of patients developed ATU when treated with ustekinumab for 1 year.(1) Therefore, it is important to monitor trough concentrations of serum UTK to correlate drug levels with loss of response to therapy. ATU may increase drug clearance in treated patients or neutralize the drug effect, thereby potentially contributing to the loss of response. ATU could also cause adverse events, such as serum sickness and hypersensitivity reactions.
Currently, ustekinumab quantitation is performed in conjunction with immunogenicity assessment for ATU.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
USTEKINUMAB QN, S:
Limit of quantitation is 0.3 mcg/mL
In inflammatory bowel disease, at post-induction measurement (week 8), concentrations above 3.5 mcg/mL are associated with good outcomes.
For maintenance stages:
Concentrations > or =1.0 mcg/mL are associated with clinical response and clinical remission
Concentrations > or =4.5 mcg/mL are associated with mucosal healing
USTEKINUMAB AB, S:
Limit of quantitation is 10 AU/mL
Absent: <10 AU/mL
Present: > or =10 AU/mL
Interpretation
Provides information to assist in interpretation of the test results
| Antibodies to ustekinumab (ATU) absent | ATU present | |
| Ustekinumab quantification <1.0 mcg/mL | For nonresponders: | For nonresponders: |
| Ustekinumab quantification > or =1.0 mcg/mL | For nonresponders: | For nonresponders: |
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This assay measures free ustekinumab (UTK) and free antibodies to ustekinumab (ATU). This assay does not measure UTK bound to ATU (immunocomplexes).
Presence of UTK at concentrations greater than 1 mcg/mL may impair detection of ATU, as the ATU assay is not drug tolerant.
Elevated rheumatoid factor (RF) may falsely increase results of ATU. During validation studies, negative ATU samples remained negative and positive ATU samples remained positive; however, the quantitative result differed by more than 20% when compared to the non-RF spiked original samples. If patients are positive for RF, clinical correlation is recommended for ATU test interpretation.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Stelara (ustekinumab). Package insert: Prescribing information. Janssen Pharmaceuticals; revised 03/2020
2. Papamichael K, Cheifetz AS, Melmed GY, et al. Appropriate therapeutic drug monitoring of biologic agents for patients with inflammatory bowel diseases. Clin Gastroenterol Hepatol. 2019;17(9):1655-1668.e3
Method Description
Describes how the test is performed and provides a method-specific reference
Ustekinumab (UTK) quantitation and anti-ustekinumab antibody measurements are performed using enzyme-linked immunosorbent assay. Microwell strips are pre-coated with UTK or anti-UTK antibody . Calibrators, controls, and patient samples are added to separate wells, allowing either UTK or antibodies to ustekinumab (ATUs) to bind to immobilized antigen. Unbound sample is washed away, and a second horseradish peroxidase-labeled anti-UTK or UTK (conjugate) is added to each well. A second incubation step allows the conjugate to bind to the UTK or ATU that has become attached to the microwells. After washing away the excess of unbound conjugate, the remaining enzyme activity is determined by adding a substrate and measuring the intensity of the color that develops in a spectrophotometer. The signal obtained is proportional to the amount of UTK or ATUs in the patient sample.(Unpublished Mayo method)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday, Wednesday, Friday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
80299
83520
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| USTEK | Ustekinumab QN with Antibodies, S | In Process |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| USQN | Ustekinumab QN, S | 87408-1 |
| USTAB | Ustekinumab Ab, S | 87409-9 |