Frequently Asked Questions

General

Please complete the online or fax the completed Synovasure Physician Enrollment Form to CD Laboratories at 410-415-1951 (or email to [email protected]). Enrollments are typically processed within 72 hours of receipt. To order kits, contact you local Zimmer Biomet distributor or call Zimmer Biomet Customer Service at 800-348-2759 (Option 1).

Synovasure Comprehensive Infection Panel testing is exclusively serviced by CD Laboratories® (CLIA License# 21D0216863), a subsidiary of Zimmer Biomet, located in Baltimore, MD.

As part of the Synovasure Comprehensive PJI Panel the following tests are performed:

  • Synovasure Alpha Defensin for PJI (includes alpha defensin and CRP)
  • Synovasure Microbial Identification
  • Synovasure Neutrophil Elastase
  • Culture
  • WBC count with differential

Optional Add-on: Crystal Analysis

In addition, specimen integrity testing is performed on all specimens received at CD Laboratories for PJI testing.

As part of the Synovasure Comprehensive NSA Panel the following tests are performed:

  • Synovasure Alpha Defensin for NSA (includes alpha defensin and lactate)
  • Synovasure Microbial Identification
  • Synovasure Neutrophil Elastase
  • Culture
  • WBC count with differential
  • Crystal Analysis

In addition, specimen integrity testing is performed on all specimens received at CD Laboratories for NSA testing.

The Synovasure Infection Transportation kit contains the materials needed to send synovial fluid specimens to CD Laboratories including:

  • Submission Instructions Sheet
  • 95 kPa Specimen Transport Biohazard Bag
  • Specimen Tubes (2 clear top, red stopper and 1 Lavender top)
  • Test Requisition Form
  • Biological Specimen Box
  • Prepaid FedEx Pouch for Biological Specimens
  • Prepaid FedEx shipping label
  • Patient record labels (x4)

After the testing is completed, results are sent via a protected PDF email or fax, as noted as the preferred method by practice upon enrollment with CD Laboratories®.

Results are provided for all tests requested and are intended to be used in conjunction with other clinical and diagnostic findings to aid a patient’s diagnosis. For description of each test, refer to the reverse side of the Test Requisition Form, Results Report, or click here.

Most test results are available within 24 hours of the receipt of specimen at CD Laboratories except Culture. At CD Laboratories, specimens are held to culture for 7 days (14 days for shoulder specimens). To ensure quick turnaround, please ensure that the test requisition form is fully completed and tubes are labeled with patient name and date of birth. Failure to do so will result in specimen processing delays.

The physician’s office can track the shipment using the tracking number on the FedEx return label provided in the Synovasure Infection Specimen Transportation Kit.

Specific shipment instructions are provided on the Test Submission Instructions included in each kit to ensure that the specimens are picked up and delivered in a timely fashion. To schedule your “prepaid pickup”, call 1-800-463-3339 (1-800-GOFEDEX).

Note: Packages CANNOT be placed in a FedEx dropbox.

If you aspirate a synovial fluid sample on Friday or over the weekend, please refrigerate the specimen and ship it on Monday. A sample can be refrigerated for up to 3 days.

Synovasure® Alpha Defensin ELISA

Synovasure Alpha Defensin ELISA test is a Laboratory Developed Test (LDT) that uses synovial fluid to aid in the diagnosis of joint infection. The test is available in two (2) formats: Synovasure Alpha Defensin for Periprosthetic Joint Infection (PJI) and Synovasure Alpha Defensin for Native Septic Arthritis (NSA).

The Synovasure Alpha Defensin for PJI Test includes: 

  • Measurement of synovial fluid alpha defensin 
  • Measurement of synovial fluid CRP

The Synovasure Alpha Defensin for NSA Test includes:

  • Measurement of synovial fluid alpha defensin 
  • Measurement of synovial fluid lactate

Several studies have evaluated the performance of Synovasure Alpha Defensin to aid in the diagnosis of Periprosthetic Joint Infection (PJI) using the Musculoskeletal Infection Society (MSIS) definition of infection as the “gold standard”. These studies have shown a combined 95% Sensitivity and 97% Specificity1.

In a clinical study, Synovasure Alpha Defensin outperformed the LE test strip in both accuracy and the ability to provide valid results. The LE strip yielded a sensitivity of 69% and was unreadable due to blood contamination 17% of specimens. Conversely, the alpha defensin assay could be read in all specimens and yielded a sensitivity of 100%2

Synovasure® Alpha Defensin is intended to assess an arthroplasty for Periprosthetic Joint Infection (PJI) prior to surgical revision. At this time, the test is not validated for use in timing of reimplantation

Clinical studies have shown that the Synovasure Alpha Defensin test is unaffected by the prior administration of antibiotics3,4

Saline washing is not approved as a collection method for Synovasure Alpha Defensin, as this will dilute the protein levels in the synovial fluid and potentially yield false negative results.

It is not recommended to utilize a contrast agent, as it will dilute the protein levels in the synovial fluid and potentially yield false negative results.

Synovasure® Microbial Identification

Synovasure Microbial ID test is a bead-based antigen test that identifies common organisms that potentially cause Periprosthetic Joint Infection (PJI) in 24 hours.

Synovasure Microbial ID test identifies more than 70%5 of organisms that cause PJI including:
  • Staphylococcus species
  • Enterococcus species
  • Candida species
  • C. acnes
In addition, the test has demonstrated the ability to identify 54% of culture-negative organisms6.

Generally, culture typically takes 3 or more days to complete, whereas the Synovasure Microbial Identification test identifies organisms in 24 hours. It is recommended that culture be performed with Synovasure Microbial Identification to obtain susceptibility for organisms.

Billing - Patient

The invoice you received is for laboratory services provided by CD Laboratories, which were ordered by your physician. This invoice is for laboratory testing fees only and is separate from any bill you may have received from your physician and/or paid at your physician’s office. Please refer to the message on your CD Laboratories invoice or the EOB from your insurance plan for more specific information about why you received an invoice. A few reasons you may have received an invoice include, but are not limited to, the following:

  • Insurance information was not received, or the wrong insurance information was received on your test order
  • The insurance plan processed the claim and denied payment
  • The insurance plan processed the claim and applied the balance to your co-pay or deductible
  • The insurance plan did not respond to the claim

If you have additional questions or concerns, please contact your insurance plan directly. Their contact information is listed on the back of the patient’s insurance card.

If you would like further assistance, please call CD Laboratories’ Billing Department at (410) 296-1400, Option 3 or email your question to [email protected].

For information regarding coverage and benefits from your insurance plan, please contact your insurance plan directly. Their contact information is listed on the back of your insurance card. Information about how a specific claim is processed should be provided to you by your insurance plan on an Explanation of Benefits (EOB) form.

No, CD Laboratories does not know each patient’s insurance coverage. It is the patient’s responsibility to verify benefits before services are performed. Any questions regarding coverage should be directed to your insurance plan. Their contact information is listed on the back of your insurance card.

It is the patient’s responsibility to verify benefits before services are performed. Any questions regarding coverage should be directed to your insurance plan at the contact information listed on the back of the insurance card.

Billing - Provider

First, a practice will need to obtain prior authorization (PA) from the patient’s insurance plan to perform the joint aspiration (arthrocentesis) and have the laboratory testing conducted by CD Laboratories. If approved, the PA number should be entered into the field on the Test Requisition Form. If PA cannot be obtained, the practice should seek alternative testing or have the patient determine whether to accept financial responsibility for the testing.

The physician will perform the joint aspiration (arthrocentesis) and bill the patient’s insurance plan as normal, using existing CPT® codes (e.g., 20610, 20611)*.

CD Laboratories will verify the patient’s insurance and PA information. Upon running the specimen, CD Laboratories will bill the patient’s insurance plan for the tests selected on the Test Requisition Form. If PA was denied and/or the patient accepted financial responsibility for the test, an invoice will be sent to the patient requesting payment.

If the arthrocentesis is being performed within a hospital (i.e., the patient is an inpatient or outpatient of a hospital), the hospital is required to bill Medicare for the test. CD Laboratories will serve as a reference laboratory in these scenarios and will bill the hospital for the services performed. Payment to the hospital will be based upon the applicable Medicare payment system for inpatient or outpatient services.

*Current Procedural Terminology (CPT®) copyright 2019 American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association.

It is recommended that prior authorization (PA) be obtained from the patient’s insurance plan prior to the arthrocentesis and shipment of the specimen. The PA needs to specify that the laboratory test(s) will be performed by CD Laboratories. If approved, the PA number should be entered into the Test Requisition Form. CD Laboratories will bill the patient’s insurance upon performing the requested test(s). If the patient’s insurance plan declines coverage, the patient is responsible to cover the cost of the tests.

A customer should obtain Prior Authorization from the patient’s insurance or agreement from a patient on financial responsibility prior to submitting a specimen. Prior Authorization information should be included on the Test Requisition Form.

For Reimbursement questions, please contact the Zimmer Biomet Reimbursement Hotline by calling 866-946-0444 or emailing [email protected]. The hotline is available from 8:00AM to 5:00PM EST Monday through Friday.

  1. Synovasure Alpha Defensin ELISA Instructions for Use (IFU).
  2. Deirmengian C., et al. The Alpha-defensin Test for Periprosthetic Joint Infection Outperforms the Leukocyte Esterase Test Strip. Clinical Orthopedics and Related Research. 473:198–203, 2015.
  3. Deirmengian C., et al. Combined Measurement of Synovial Fluid a-Defensin and C-Reactive Protein Levels: Highly Accurate for Diagnosing Periprosthetic Joint Infection. Journal of Bone and Joint Surgery. 96(17):1439-45, 2014.
  4. Shahi A., et al. The Alpha-Defensin Test for Periprosthetic Joint Infection is Not Affected by Prior Antibiotic Administration. Clinical Orthopedics and Related Research. 474(7):1610-5, 2016
  5. Synovasure Microbial Identification Instructions for Use (IFU)
  6. Deirmengian C, et al. Diagnostic Performance of the Synovasure MID Test [abstract]. In: Proceedings of the MSIS Annual Meeting; 2019 Aug 2-3; New York, NY