Tests
1st tests to order
history and physical exam
Tests to consider
x-ray of affected joints
Test
OA is essentially a clinical diagnosis.
Imaging studies are not routinely recommended for the diagnosis of OA, they should only be considered if the diagnosis is unclear or an alternative/additional diagnosis is suspected subsequent to initial investigations.[73]
If imaging studies are required, radiography should be considered before other imaging modalities.[77][79] If imaging the foot and ankle, avoid nonweightbearing radiographs if the patient is able to stand.[81]
Conventional radiographic diagnosis of OA includes narrowing of the joint space, osteophytes, subchondral cysts, and subarticular sclerosis.[79][80]
Radiographs may also help to exclude less common etiologies for pain and in monitoring unexpected rapid progression or changes in symptoms that may be related to OA severity or an additional diagnosis.[77]
Result
new bone formation (osteophytes), joint space narrowing, and subchondral sclerosis and cysts
serum CRP
Test
OA is essentially a clinical diagnosis.
If there are atypical features that suggest an alternative or additional diagnosis, laboratory investigations may be warranted.
Inflammatory markers may be ordered if inflammatory arthritis, such as rheumoatoid arthritis (RA), is suspected.[3][78]
It should be noted that elevated inflammatory markers are also associated with age, increased weight, and other conditions; therefore, they should not be interpreted as definitive evidence of inflammatory conditions in the absence of other symptoms.
Result
normal
serum erythrocyte sedimentation rate (ESR)
Test
OA is essentially a clinical diagnosis.
If there are atypical features that suggest an alternative or additional diagnosis, laboratory investigations may be warranted.
Inflammatory markers may be ordered if inflammatory arthritis, such as rheumatoid arthritis, is suspected.[3][78]
It should be noted that elevated inflammatory markers are also associated with age, increased weight, and other conditions; therefore, they should not be interpreted as definitive evidence of inflammatory conditions in the absence of other symptoms.
Result
normal
rheumatoid factor (RF)
Test
OA is essentially a clinical diagnosis.
If there are atypical features that suggest an alternative or additional diagnosis, laboratory investigations may be warranted.
Indicated if rheumatoid arthritis (RA) cannot be excluded clinically, or if there is a suspicion that the patient might have both RA and OA.[3]
Result
negative
anticyclic citrullinated peptide (anti-CCP) antibody
Test
OA is essentially a clinical diagnosis.
If there are atypical features that suggest an alternative or additional diagnosis, laboratory investigations may be warranted.
Indicated if rheumatoid arthritis (RA) cannot be excluded clinically or if there is a suspicion that the patient might have both RA and OA.
Result
negative
MRI of affected joints
Test
Imaging studies are not routinely recommended for the diagnosis of OA, they should only be considered if the diagnosis is unclear or an alternative/additional diagnosis is suspected subsequent to initial investigations.[73]
Although more sensitive than plain radiographs in detecting OA changes, MRI is not indicated for the diagnosis of simple OA. If needed, MRI should be ordered if spinal OA with neurologic deficits is suspected, to identify and evaluate the extent and severity of spinal stenosis or nerve root entrapment.
MRI can be is used to rule out other etiologies for hip or knee pain, such as avascular necrosis or other less common conditions such as pigmented villonodular synovitis or bone tumors.[77][79]
Bone marrow lesions (edema), which are associated with knee pain in OA, are readily detected using MRI.[79][83][84] Medial and lateral compartment bone marrow lesions confer increased risk of progression of medial and lateral tibiofemoral OA, respectively.[85]
Result
cartilage loss, bone marrow lesions, and meniscal tears
ultrasound scan
Test
OA is essentially a clinical diagnosis.
Imaging studies are not routinely recommended for the diagnosis of OA, they should only be considered if the diagnosis is unclear or an alternative/additional diagnosis is suspected subsequent to initial investigations.[73]
Ultrasound scans can be used to make additional diagnoses.
Soft tissues are best imaged by ultrasound or MRI.[77]
Result
effusion, synovial hypertrophy, cartilage loss
CT
Test
OA is essentially a clinical diagnosis.
Imaging studies are not routinely recommended for the diagnosis of OA, they should only be considered if the diagnosis is unclear or an alternative/additional diagnosis is suspected subsequent to initial investigations.[73]
CT can be used to make additional diagnoses.
Bones are best imaged by CT or MRI.
In practice, CT is not widely used for the diagnosis of OA.
Result
osteophytes, bone or cartilage loss
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