Synovasure® Alpha Defensin ELISA Laboratory Test

Periprosthetic Joint Infection (PJI) is one of the most common complications following total joint arthroplasty, accounting for 25% of total knee arthroplasty failures and 16% of total hip arthroplasty failures.1

What is Alpha Defensin?

Alpha Defensin is an antimicrobial peptide released into the body through activated neutrophils in response to an infection. In cases of PJI, a patient will have elevated levels of alpha defensin in their synovial fluid.

Clinical findings show that alpha Defensin test results are not influenced by:

  • Prior antibiotic administration2,3
  • Comorbidities related to inflammation2
  • Type and/or virulence of the organism2,4

Since discovery, alpha defensin has aided in the diagnosis of PJI following total joint replacement. In 2018, alpha defensing biomarker was included as a minor criteria for diagnosing PJI by the International Consensus Meeting (ICM) on Joint Infection.5

Synovasure® Alpha Defensin ELISA Test*

First and only laboratory test specifically designed and validated to aid in the diagnosis of PJI. The ELISA test identifies elevated levels of Alpha Defensin, a critical protein in the innate immune response to infection.

Proprietary Test for Synovial Fluid
Alpha Defensin ELISA Laboratory testing is only available from CD Laboratories.

Unparalleled accuracy

95% sensitive and 97% specific using the 2013 MSIS criteria for diagnosing PJI. 2, 6-11





Rothman Institute2


97% (36/37)

96% (107/112)

Mayo Clinic6


100% (19/19)

95% (40/42)

Cleveland Clinic7


100% (24/24)

98% (53/54)

Endo Klinik8


97% (28/29)

97% (123/127)

Cleveland Florida9


97% (34/35)

97% (34/35)

Charite – Universitatsmedizin Berlin10


85% (11/13)**

98% (57/58)

Multi-center Study11***


93% (113/122)

98% (241/247)



95% (265/279)

97% (655/675)

**Includes patients with a draining sinus
***Mayo Clinic, Cleveland Clinic – Florida, Sinai Hospital of Baltimore


Performance backed by data

  • Prior antibiotic administration2,3
  • Comorbidities related to inflammation2
  • Type and/or virulence of the organism2,4 

Additional Information

  1. Diermengian C, et al. Diagnosing Periprosthetic Joint Infection: Has the Era of the Biomarker Arrived? Clin Orthop Relat Res.  Nov;472(11):3254-62, 2014.
  2. Diermengian C, et al. Combined Measurement of Synovial Fluid a-Defensin and C-reactive Protein Levels: Highly Accurate for Diagnosing Periprosthetic Joint Infection. JBJS Am. Sep 3;96(17):1439-45, 2014.
  3. Shahi A, et al. The alpha-defensin Test for Periprosthetic Joint Infections is Not Affected by Prior Antibiotic Administration. Clin Orthop Relat Res. Jul;474(7):1610-5, 2016.
  4. 4. Diermengian C, et al. The C-reactive Protein May Not Detect Infections Caused by Less-Virulent Organisms. Journal of Arthroplasty. 31:152-155, 2016. 
  5. Amanatullah D, et al. Hip and Knee Section, Diagnosis, Definitions: Proceedings of International Consensus on Orthopedic Infections. Journal of Arthroplasty. 34(2019) S329eS337.
  6. Bingham J., et al. The alpha Defensin-1 Biomarker Assay can be Used to Evaluate the Potentially Infected Total Joint Arthroplasty. Clin Orthop Relat Res  DOI 10.1007/s11999-014-3900-7. 
  7. Frangiamore S., et al. a-Defensin Accuracy to Diagnose Periprosthetic Joint Infection – Best Available Test? JOA. 312:456-60, 2016. 
  8. Bonanzinga,T., et al. How Reliable Is the Alpha-defensin Immunoassay Test for Diagnosing Periprosthetic Joint Infection? A Prospective Study. Clin Orthop Relat Res DOI 10.1007/s11999-016-4906-0. 
  9. Kanwar S, et al. What is the optimal criteria to use for detecting periprosthetic joint infections before total joint arthroplasty? Journal of Arthroplasty. 33:S201e4, 2018.
  10. Sigmund I., et al. Is the Enzyme-linked Immunosorbent Assay More Accurate Than the Lateral Flow Alpha Defensin Test for Diagnosing Periprosthetic Joint Infection?. Clin Orthop Relat Res. 476:1645-1654, 2018. 
  11. CDD-CLI-001: Clinical Validation of CD Diagnostics Synovasure PJI ELISA Test and Synovasure PJI Lateral Flow Test for Detection of Periprosthetic Joint Infection (PJI) in Synovial Fluid. 
*Synovasure Alpha Defensin ELISA Test is intended for use as an adjunct test to current methods and can be requested individually or as part of the Comprehensive PJI Laboratory Test Panel.

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


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