Arthritis Testing at CD Laboratories

Arthritis is one of the most common reasons for knee pain and can come in many different forms including Osteoarthritis (OA), Rheumatoid Arthritis (RA), Crystal Arthritis (such as gout) and Septic (Infectious) Arthritis. Many times, these forms of arthritis have similar symptoms, but their treatments and potential post-operative risks can vary. It is also not uncommon for patients to be affected by more than one form of arthritis, making an accurate diagnosis a key part of your doctor’s treatment plan. At CD Laboratories, it is our goal to help your physician determine what may be causing your knee pain and aid in the development of a more informed treatment plan to mitigate post-operative risks.

Why is an Accurate Arthritis Diagnosis Important?

There are numerous types of arthritis that can cause knee pain. Depending on which type is causing your knee pain, your doctor may choose different treatments ranging including non-surgical (i.e. injections, etc.) to surgical options. In situations where surgery is recommended, the type of arthritis may also influence the implant selection, location and care plan prior to and after the surgery. These decisions are driven by clinical evaluation, imaging (X-ray, MRI) and laboratory testing.

What is Included as Part of the Test Panel?

Our test panel includes tests for biomarkers, or proteins within the body, that are commonly associated with the presence of the most common arthritis conditions causing knee pain – Osteoarthritis (OA), Rheumatoid Arthritis (RA), Crystal Arthritis, and Native Septic Arthritis. These biomarkers can also give indications of potential post-operative risks following knee replacement. Using a single joint fluid sample, the panel of tests evaluates the levels of those markers.

The panel tests for 2 markers that can indicate the presence of OA – COMP and IL-8. When the results are combined, these markers are highly effective in diagnosing the presence of OA as a primary or secondary condition1.

The panel additionally tests for 2 markers that can indicate your pain is caused by RA – Anti-CCP and Rheumatoid Factor. Combined, these markers are effective in identifying the possibility of RA causing your knee pain.

The test panel evaluates the fluid for the presence of crystals (commonly associated with gout) using a high-powered microscope.

The panel evaluates the level of white blood cells (WBCs) injoint fluid. If the levels are elevated, the fluid is also tested for infection specific tests:

  • Alpha defensin – a protein created by the body to fight infection
  • Lactic acid – commonly elevated in cases of septic arthritis
  • Culture – Further identification of potential organism causing infection, as well as what antibiotic may aid in treatment

Why Choose the Synovasure RISC® Panel for Arthritis Testing?

With over 400,000 joint fluid samples tested to date, CD Laboratories is an expert in joint fluid testing. From a single joint fluid sample, we provide you and your doctor with results to differentiate between the most common arthritis conditions causing knee pain, in 72 hours. Our testing includes the FIRST test designed specifically to diagnose Osteoarthritis (OA), while others are only to exclude OA from a diagnosis.
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How Does the Testing Work?

Your doctor will take a sample of fluid from your painful knee

Fluid is packaged and shipped overnight to CD Laboratories (located outside Baltimore, MD)

Testing is performed and results are sent to doctor within 72 hours of receipt at laboratory

Frequently Asked Questions (FAQs)

While other labs are capable of performing tests that are part of the Synovasure RISC® Panel, this specific panel of tests using a single joint fluid sample is only available through CD Laboratories. In addition, our Osteoarthritis (OA) testing is the only test available that is designed to diagnosis OA, while others only exclude it from a diagnosis.

The 2024 price for the Synovasure RISC® Panel is $188.00. If white blood cell counts are elevated and additional testing is required via the Synovasure Alpha Defensin for Native Septic Arthritis (NSA) an additional $143.00 will be charged for a maximum charge of $331.00. 

Please note that Synovasure RISC® Panel testing is not available in New York State.

*Note: Pricing is effective as of September 2026 and is subject to change

For patients with traditional Medicare insurance, CD Laboratories will bill Medicare directly on behalf of the patient for testing, as well as any secondary insurances that the patient may have.

For non-Medicare patients, CD Laboratories will bill the patient directly for testing. As a courtesy, a claim will also be submitted to the patient’s insurance for reimbursement. Any available reimbursement will be provided directly back to the patient from their insurance company.

Yes. We will bill Medicare and a patient’s secondary insurance directly on behalf of the patient for Synovasure RISC® Panel testing.

Payment for Synovasure RISC® Panel can be made via:

  • Flexible Spending Account (FSA)
  • Health Savings Account (HSA)
  • Credit Card
  • Check

Follow the instructions on your bill to complete payment.

Yes. Payment plans are available over three (3) equal monthly payments. For more information, please contact 855.731.4550. 

Your signature is needed to allow us to submit a claim to your insurance company on your behalf. The signature also acknowledges your acceptance of financial responsibility for any necessary billing.

Yes, for most patients CD Laboratories is an out-of-network provider as it is located in Maryland. The Synovasure RISC® Panel testing is only available through CD Laboratories as it is proprietary to our laboratory, so testing cannot be performed at any other laboratory including LabCorp or Quest Diagnostics. For more information regarding our status as out-of-network, click here.

To obtain a copy of your results, please contact your doctor’s office. They will have record of the results provided by CD Laboratories. If your doctor requires a new copy for their records, they should contact CD Laboratories Customer Service at 888-981-8378 (Monday through Friday from 8AM to 6PM EST)

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