Synovasure Differential Diagnosis Arthritis Panel

Guiding Your Arthritis Diagnosis

One-stop, comprehensive panel of synovial fluid laboratory tests

Synovasure Differential Diagnosis Arthritis Panel is the first of its kind laboratory test panel to aid in a differential arthritis diagnosis of the knee; offered exclusively by Zimmer Biomet via its facility, CD Laboratories. The lab, located in Baltimore, MD, is certified under the Clinical Laboratory Improvement Amendments (CLIA) from the Centers for Disease Control (CDC). Focused on joint fluid testing, the lab currently processes over 40,000 specimens per year to assess for joint infection and now expanded to aid in identifying and diagnosing between multiple forms of arthritis in the knee.

A Single Aspiration for Comprehensive Results

The Synovasure Differential Diagnosis Arthritis Panel provides physicians multiple results to help discern between arthritis conditions causing knee pain with similar symptoms and aid in identification of potential secondary arthritis conditions with a single synovial fluid knee aspiration. As part of the Synovasure Differential Diagnosis panel, a variety of tests are performed to assess levels of biomarkers associated with some of the most common musculoskeletal arthritis conditions:

  • Native Septic Arthritis (NSA)
  • Osteoarthritis (OA)
  • Rheumatoid Arthritis (RA)
  • Crystalline Arthritis (ie. gout)


Accuracy of synovial fluid diagnostic tests can be significantly impacted by the quality of the specimen submitted. Every specimen received at CD Laboratories for the Synovasure Differential Diagnosis Arthritis panel is tested for specimen integrity (A280 Absorbance and Red Blood Cell count). If specimen is suboptimal, physicians are notified in their results.

Streamlined Submission and Results Process

  • Overnight shipment to CD Laboratories
  • Results within 3 business days
  • Simple, easy to read report designed specifically for arthritis
Synovasure Diagnostic 1000x1000px Graphics-Streamlined Process

Native Septic Arthritis testing includes White Blood Cell (WBC) count with differential, which is an automated, high-performance cell count that provides overall number of white blood cells, as well as the percentage breakdown of white blood cell type in synovial fluid.

  • All counts >3,000 confirmed with a manual count
  • If the final reported WBC count is >3,000 cells/μL or neutrophils percent is >70%, specimens are reflexed to the Synovasure Alpha Defensin for Native Septic Arthritis (NSA) test

The Synovasure Alpha Defensin for NSA test examines the levels of the alpha defensin biomarker and lactate in synovial fluid.

The alpha defensin biomarker has shown to be highly accurate in diagnosing the presence of periprosthetic joint infection1 and is unaffected by:

  • Prior Antibiotic Administration2,3
  • History of Inflammatory Conditions2,4
  • Type/Virulence of Organism2,5

Note: Validation and performance of alpha defensin is based on cases of PJI and has not been defined for NSA due to no comparative “Gold Standard” criterion.

The first laboratory test to aid in the diagnosis of OA, Synovasure OA testing includes assessment of Cartilage Oligomeric Matrix Protein (COMP) and Interleukin-8 (IL-8) concentration levels in synovial fluid.

  • Only laboratory test available to aid in the diagnosis of isolated, idiopathic OA
  • Utilization of COMP/IL-8 ratio to differentiate primary versus secondary OA patients
    • Increased IL-8 shows higher likelihood of inflammatory condition compared to OA
  • Highly Accurate6
    • 87.0% Sensitivity
    • 88.9% Specificity 

Rheumatoid Arthritis diagnostic testing includes synovial fluid assessment of inflammatory biomarkers concentrations commonly tested via blood – Anti-Cyclic Citrullinated Peptide (Anti-CCP) and Rheumatoid Factor (RF).

  • Testing closer to the knee pain source – synovial fluid vs. blood
  • Sufficiently capable to discriminate RA and Non-RA patients6
  • Effective “Rule-In” Test6
    • Demonstrated 100% specificity 

High powered microscopy to assess synovial fluid for the presence of Monosodium Urate (MSU) and Calcium Pyrophosphate Dihydrate (CPPD) crystals commonly found in Crystalline arthritis (gout and pseudogout).

Legal Manufacturer:

CD Diagnostics
650 Naamans Road
Suite 100
Claymont, DE 19703 USA


  1. Synovasure Alpha Defensin ELISA Test Instructions for Use (IFU), 2018.
  2. 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.
  3. 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.
  4. Miyamae Y., et al. Diagnostic Accuracy of the Alpha-Defensin Test for Periprosthetic Joint Infection in Patients with Inflammatory Diseases. Journal of Arthroplasty. 34(8):1767-1771, 2019.
  5. Deirmengian C., et al. The C-reactive Protein May Not Detect Infections Cause by Less-Virulent Organisms. Journal of Arthroplasty. 31(9 Suppl):152-5, 2016.
  6. 12514-009 – Technical Report: Performance of Synovasure® Differential Diagnosis Arthritis Panel Diagnostic Accuracy Test, 2020.

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For product information, including indications, contraindications, warnings, precautions, potential adverse effects and patient counseling information, see the package insert and information on this website. To obtain a copy of the current Instructions for Use (IFU) for full prescribing and risk information, please call 1-800-348-2759, press 4 for 411 Technical Support.