Synovial Fluid Albumin Test

What is this test?

The Synovial Fluid Albumin test measures the amount of albumin in the fluid that lubricates your joints (synovial fluid). Albumin is a protein produced by your liver that helps maintain fluid balance and transports various substances throughout your body. This test uses a technique called electrophoresis, which separates different proteins in the fluid so they can be measured individually.

How is the test performed?

A healthcare provider will first clean the area over the affected joint. Then, they will insert a thin needle into the joint space to withdraw a small amount of synovial fluid (this is called joint aspiration or arthrocentesis). The fluid sample is sent to a laboratory where electrophoresis is used to separate and measure the albumin content. You may feel some discomfort or pressure during the needle insertion, but the procedure is generally quick.

Why is this test ordered?

Your doctor may order this test if you have joint pain, swelling, stiffness, or reduced range of motion. The test helps distinguish between different types of joint conditions, such as osteoarthritis, rheumatoid arthritis, gout, or joint infections. By analyzing the protein pattern in your synovial fluid, doctors can better understand what is causing your joint symptoms.

What do the results mean?

Normal synovial fluid has a specific pattern of proteins, including albumin. Abnormal results may show changes in albumin levels or the pattern of other proteins. Lower than normal albumin may indicate inflammatory conditions like rheumatoid arthritis. Higher levels or an altered protein pattern might suggest degenerative conditions or joint damage. Your doctor will interpret your results along with your symptoms and other test findings.