Test Id : ALDEF
Alpha Defensin, Lateral Flow Assay, Synovial Fluid
Useful For
Suggests clinical disorders or settings where the test may be helpful
Detection of alpha defensins 1-3, human host response proteins, in synovial fluid of adults with a total joint replacement who are being evaluated for revision surgery
This test is not intended to be used to determine timing for reimplantation in 2-stage procedures.
Method Name
A short description of the method used to perform the test
Lateral Flow Assay (LFA)
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
Prosthetic joint infection
PJI
Alpha Defensin
ALDEF
Alpha-defensin
Synovasure
Specimen Type
Describes the specimen type validated for testing
Synovial Fluid
Ordering Guidance
This test should only be used for patients with a total joint prosthesis.
Necessary Information
Specimen source and type of joint are required. If not obtained from a prosthetic joint, testing will be canceled.
If ordering electronically, answers must be provided for the order entry questions.
If not ordering electronically, specimen source and type of joint must be provided on the request form.
ORDER QUESTIONS AND ANSWERS
| Question ID | Description | Answers |
|---|---|---|
| JOINT | Is this for a prosthetic joint? |
Yes No Unknown |
| ADSRC | Alpha Defensin Source |
Synovial Fluid, Left Ankle Synovial Fluid, Right Ankle Synovial Fluid, Left Elbow Synovial Fluid, Right Elbow Synovial Fluid, Left Hip Synovial Fluid, Right Hip Synovial Fluid, Left Knee Synovial Fluid, Right Knee Synovial Fluid, Left Shoulder Synovial Fluid, Right Shoulder Synovial Fluid, Left Wrist Synovial Fluid, Right Wrist Unknown |
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: Plain red-top tube
Submission Container/Tube: Plastic vial
Specimen Volume: 0.6 mL
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.
0.10 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | 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 |
|---|---|---|---|
| Synovial Fluid | Refrigerated | 7 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Detection of alpha defensins 1-3, human host response proteins, in synovial fluid of adults with a total joint replacement who are being evaluated for revision surgery
This test is not intended to be used to determine timing for reimplantation in 2-stage procedures.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Diagnosis of prosthetic joint infections (PJI) may be challenging in certain clinical scenarios. Multiple societies have defined criteria for establishing the presence of a PJI, including results from laboratory tests, clinical findings, and tissue histopathology. The challenge, however, is that results of these tests are frequently not available at the time of or after surgery. As an alternative, determining the cell count and differential on synovial fluid are frequently used biomarkers for PJI, however there is a lack of consensus on the optimal thresholds to use for a PJI diagnosis. Additionally, cell count and differential results require clinician interpretation as laboratories do not report abnormal levels correlating with PJI.
Alpha defensins are antimicrobial peptides released by activated neutrophils in response to infection and served as part of the host-defense innate immune system with broad antimicrobial activity against gram-positive and gram-negative bacteria, mycobacteria, fungi, and viruses. The presence of alpha defensins in synovial fluid may therefore be used by clinicians as a marker of PJI.
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.
Negative
Reference values apply to all ages.
Interpretation
Provides information to assist in interpretation of the test results
Negative:
No alpha defensin detected in synovial fluid, suggesting absence of prosthetic joint infection.
Positive:
Alpha defensin in synovial fluid detected suggesting presence of prosthetic joint infection. Additional microbiologic studies (eg, culture, molecular detection) are recommended.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Alpha defensin testing should be used to evaluate for the presence of a prosthetic joint infection if other clinical and diagnostic test findings (ie, synovial fluid cell count and differential) are inconclusive.
Test results should be utilized in conjunction with other clinical and diagnostic findings to aid the diagnosis of prosthetic joint infection.
This kit has been developed for use with freshly collected synovial fluid only. The use of this test kit with any other specimen type may lead to inaccurate test results. The use of synovial fluid diluted with saline, blood, contrast agent, or any substances injected into the joint may lead to false–negative results.
Presence of greater than 1 million/mcL red blood cells in the synovial fluid specimen may lead to false-negative results. This represents dilution of the synovial fluid specimen with greater than 20% blood.
The performance of this test has only been validated for conditions evaluated by the Musculoskeletal Infection Society criteria.
A decrease in sensitivity (an increased likelihood of false-negative results) has been observed in the presence of a sinus tract communicating with the prosthesis. Since the presence of a sinus tract is definitive evidence of PJI, use of this test under those circumstances is not recommended.
False-positive results have been reported in the presence of metallosis.
A negative test result does not preclude the possibility of infection.
Synovial fluid obtained after repeated aspirations within a short time period might lead to false–negative results due to the lack of buildup of alpha defensin.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
Bonanzinga T, Ferrari MC, Tanzi G, Vandenbulcke F, Zahar A, Marcacci M. The role of alpha defensin in prosthetic joint infection (PJI) diagnosis: a literature review. EFORT Open Rev. 2019;4(1):10-13
Method Description
Describes how the test is performed and provides a method-specific reference
The Alpha Defensin Lateral Flow Test Kit is an immunoassay test system comprised of a single use device, a premeasured vial of dilution buffer, a disposable Microsafe tube, and a sample cup.
Each device contains a reagent strip with all the critical components for the assay. Dilution is performed by collecting a sample from an aspirated synovial fluid specimen using the disposable Microsafe tube and adding the sample to the premeasured dilution buffer. Three full, free-falling drops of the diluted sample are then added to the test device to begin the testing process. Cellular material is removed by the first pad. The solution then migrates to the buffering pad and mixes with the gold conjugate that has been labelled with an anti-alpha defensin antibody. The test mixture then migrates across the test line and the control line. A test result line will form if the level of alpha defensin in the sample is greater than the cut-off concentration. A control line will form to confirm that the solution has properly flowed across the device. Results can be read between 10 to 20 minutes.(Package insert: Synovasure Alpha Defensin Lateral Flow Test Kit. Zimmer Biomet; M40004 V 8, 01/2024)
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 through Friday, Sunday
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 has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
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.
83518
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 |
|---|---|---|
| ALDEF | Alpha Defensin, Synovial Fluid, LFA | 94718-4 |
| 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.
|
|---|---|---|
| 607711 | Alpha Defensin, Synovial Fl, LFA | 94718-4 |
| JOINT | Is this for a prosthetic joint? | 86955-2 |
| ADSRC | Alpha Defensin Source | 72923-6 |