A Single Source for Joint Infection Diagnosis

Joint infection can occur in a patient with a joint prosthesis (Periprosthetic Joint Infection, or PJI) or a patient without a prosthesis (Native Septic Arthritis, or NSA). Diagnosing joint infection can be challenging and making a comprehensive laboratory workup important to provide a complete view of the potential organism that may be the source of the potential infection.

At CD Laboratories, we offer comprehensive synovial fluid testing solutions to aid in the diagnosis of joint infection – Synovasure® Comprehensive PJI Panel and Synovasure Comprehensive NSA Panel – through a combination of proprietary and standard of care (SoC) tests and fulfills the 2018 International Consensus Meeting (ICM) PJI diagnosis criteria. Learn more about the criteria, click here.

Synovasure Comprehensive Infection Panels

The Synovasure Comprehensive PJI Panel offers proprietary and standard of care (SoC) tests to aid in the diagnosis of Periprosthetic Joint Infection (PJI). The panel includes:

  • Synovasure Alpha Defensin
  • Synovasure Microbial Identification*
  • Synovial Fluid C-reactive Protein (CRP)
  • Culture
  • White Blood Cell (WBC) with differential
  • Specimen Integrity

Optional Add-on: Crystal Analysis

For additional information on tests, click here

*Note: Synovasure Microbial Identification is not available in New York

The Synovasure Comprehensive NSA Panel offers proprietary and standard of care (SoC) tests to aid in the diagnosis of Native Septic Arthritis (NSA). The panel includes:

  • Synovasure Alpha Defensin for NSA (alpha defensin and lactate)
  • Synovasure Microbial Identification
  • Culture
  • White Blood Cell (WBC) with differential
  • Crystal Analysis
  • Specimen Integrity
For additional information on tests, click here
Note: Synovasure Comprehensive NSA Panel is not available in New York

Note: All specimens are tested for specimen integrity as part of the Synovasure Comprehensive Infection Panels

Synovasure Alpha Defensin ELISA

Alpha defensin is an antimicrobial peptide released in response to a pathogen in synovial fluid which is used as a biomarker to aid in the diagnosis of joint infection. 


The Synovasure Alpha Defensin ELISA Test is a laboratory-based test, only available from CD Laboratories, to detect elevated alpha defensin levels in synovial fluid.

Clinically Validated Performance

  • High sensitivity and specificity based on 2013 MSIS criteria for PJI1
  • Performance unaffected by:
    • Prior antibiotic administration2,3
    • Comorbidities related to inflammation2,4
    • Type and/or virulence of organism2,5

Synovasure Microbial Identification

Only available from CD Laboratories, the Synovasure Microbial Identification (ID) Test offers a novel method for early detection of microbial antigen of microorganism species that cause more than 70% of PJI7 in 24 hours including:

  • Staphylococcus species
  • Enterococcus species
  • Candida species
  • C. acnes

Performance Backed by Data

  • Demonstrated >94% overall panel sensitivity for the detection of microorganism species in infected synovial fluid samples6,7
  • Demonstrated >98% overall panel specificity in non-infected synovial fluid samples6,7
  • A 2023 clinical study showed the panel’s ability to detect a microorganism in >49% of culture-negative PJI samples7
Staphylococcus species
Enterococcus species
Candida species

Due to difficulty culturing C. acnes, sensitivity and specificity data is not available.

  1. M40003 – Synovasure Alpha Defensin ELISA Instructions for Use (IFU), 2023.
  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 Caused by Less-Virulent Organisms. Journal of Arthroplasty. 31(9 Suppl):152-155, 2016.
  6. M40022 – Synovasure Microbial Identification Instructions for Use (IFU), 2022.
  7. Toler K, et al. Nationwide Results of Microorganism Antigen Testing as a Component of Preoperative Synovial Fluid Analysis. The Journal of Bone and Joint Surgery, 105(6):448-454, 2023.