Question

What are the expected results for the Rheumatoid Factor experiment ?

Can someone please give me a complete answer with a good discussion . Thank you

Answer 1

The Rheumatoid factor is an IgM antibody to FC fragment of an IGG. The AGG becomes damaged and IGM is formed against it. It is the mechanism behind rheumatoid Factor.

The Rheumatoid factor binds to IgG forming immune complexes --> activation of classical complement pathway --> increase in inflammatory response ---> enzymatic destruction of cartilage and bone.

*Indication for testing the Rheumatoid factor:

To help diagnose the presence of an autoimmune disease such as rheumatoid arthritis (RA).

When is it ordered?

The test for RF may be ordered when a person has signs and symptoms of RA. Symptoms may include:

• Pain, warmth, swelling, and morning stiffness in the joints
• Nodules under the skin
• If the disease has progressed, evidence on X-rays of swollen joint capsules and loss of cartilage and bone

An RF test may be repeated when the first test is negative and symptoms persist.

Test result:

The RF test must be interpreted in conjunction with other laboratory tests and a person's signs, symptoms, and clinical history. RF is present in 70%-90% of patients with RA, though is not diagnostic of RA.

In those with symptoms and clinical signs of rheumatoid arthritis, the presence of significant concentrations of RF indicates that it is likely that they have RA. Higher levels of RF generally correlate with more severe disease and a poorer prognosis.

A negative RF test does not rule out RA. About 20% of people with RA will have very low levels of or no detectable RF. In these cases, a CCP antibody test may be positive and used to confirm RA.