Foot and ankle pain is often attributed to local musculoskeletal pathology; however, clinicians should remain alert to the possibility of underlying systemic or metabolic causes. Blood tests can play an important role in identifying these conditions, particularly where the clinical presentation is atypical, persistent, or not responding to expected management.
While many common conditions such as tendinopathy or mechanical overload do not require laboratory investigation, there are scenarios where blood tests are indicated. These include patients presenting with unexplained or disproportionate pain, bilateral or multi-joint involvement, or symptoms suggestive of inflammatory disease. Systemic features such as fatigue, morning stiffness, or a history of autoimmune or metabolic conditions should also prompt consideration of further investigation.
Inflammatory arthropathies, including rheumatoid arthritis and seronegative spondyloarthropathies, can present with foot and ankle involvement, sometimes as an early feature. Similarly, metabolic conditions such as haemochromatosis can lead to joint pain and degenerative change, often affecting the foot and ankle. Crystal arthropathies, including gout, should also be considered, particularly in patients presenting with acute or recurrent joint pain.
Blood tests may include inflammatory markers such as ESR and CRP, autoimmune markers including rheumatoid factor and anti-CCP antibodies, and metabolic investigations such as serum ferritin and transferrin saturation when haemochromatosis is suspected. Uric acid levels may be useful in the context of suspected gout, although clinical correlation remains essential.
Referral for blood tests should be considered where symptoms are not consistent with a straightforward mechanical cause, where there is poor response to appropriate conservative management, or where there is clinical suspicion of systemic disease. Early identification of these conditions is important, as management often requires input from rheumatology or other specialist services.
It is important to interpret blood test results within the broader clinical context. Abnormal findings should guide further investigation and referral, but normal results do not always exclude underlying pathology. A structured approach combining clinical assessment, imaging where appropriate, and laboratory investigation provides the most effective pathway to diagnosis.
Multidisciplinary team (MDT) working is particularly valuable in these cases. Collaboration between primary care, rheumatology, podiatry, orthopaedics, and radiology supports a more comprehensive assessment and coordinated management plan, particularly where systemic disease is identified or suspected.
For clinicians, recognising when to move beyond a purely mechanical explanation for foot and ankle pain is key to avoiding delayed diagnosis of systemic conditions. For patients, timely referral for appropriate investigation ensures earlier diagnosis, targeted treatment, and a more integrated approach to care.
