From Textbook (Diagnostic Tests) - Unit 4: The Skeletal System

rheumatoid factor (RF)

Blood test that is usually positive in patients with rheumatoid arthritis. Anti-CCP blood test measures the level of antibodies and is always increased in patients with rheumatoid arthritis.

uric acid

Blood test that has an elevated level in patients with gout and gouty arthritis

arthrography

Procedure that uses a radiopaque contrast dye that is injected into a joint. It coats and outlines the bone ends and joint capsule. An x-ray, CT scan, or MRI scan is done. MRI arthrography uses a strong magnetic field to align protons in the atoms of the patient's body. The protons emit signals to form a series of thin, successive images or "slices" of the joint. An MRI can be done with or without contrast dye. The x-ray, CT, or MRI image is an arthrogram.

bone density tests

Procedure that measures the bone mineral density (BMD) to determine if demineralization from osteoporosis has occurred (see Figure 8-26). The heel or wrist bone can be tested, but the hip and spine bones give a more accurate result. This is also known as bone densitometry. There are two types of bone density tests: DEXA (or DXA) scan and quantitative computerized tomography (QCT). A DEXA scan (dual-energy x-ray absorptiometry) uses two (dual) x-ray beams with different energy levels to create a two-dimensional image. This scan can detect as little as a 1% loss of bone. Quantitative computerized tomography uses an x-ray beam and a CT scan to create a three-dimensional image. QCT is able to measure the density of both cancellous and cortical bone. Cancellous bone is the first to be affected by osteoporosis and the first to respond to therapy.

bone scintigraphy

Nuclear medicine procedure in which a phosphate compound is tagged with the radioactive tracer technetium-99m. This is injected intravenously and is taken up into the bone. A gamma scintillation camera detects gamma rays from the radioactive tracer. Areas of increased uptake ("hot spots") indicate arthritis, fracture, osteomyelitis, cancerous tumors of the bone, or areas of bony metastasis. The nuclear medicine image is a scintigram.

x-ray

Procedure that uses x-rays to diagnose bony abnormalities in any part of the body. X-rays are the primary means for diagnosing fractures, dislocations, and bone tumors.