Potential second-line investigations for pyrexia of unknown origin
| Infection | Inflammatory | Neoplastic | Miscellaneous |
|---|---|---|---|
|
Echocardiogram, preferably TOE Line cultures if the patient has an intravascular device Lumbar puncture Lymph node biopsy Malaria screen (RDT and three malaria films on consecutive days) PET-CT Serology for viral hepatitis Specialised serological or molecular tests Spinal MRI Sputum test for culture (consider an induced sputum test if the patient is not expectorating) Stool samples for culture, PCR and OCP Syphilis serology Two to three peripheral blood cultures Urine culture, plus three early morning urines for TB culture in sterile pyuria Wound swabs | ANA ANCA Anti-CCP Antiphospholipid antibodies (lupus anticoagulant and anticardiolipin) Complement levels Cryoglobulins CT chest, abdomen and pelvis Ferritin Joint aspiration to detect crystals LDH MR or CT angiography PET-CT Rheumatoid factor Serum ACE level Serum electrophoresis Serum urate Temporal artery biopsy Urine for Bence Jones protein | Colonoscopy CT chest, abdomen and pelvis Echocardiogram, preferably TOE LDH PET-CT Serum calcium Serum electrophoresis Tissue, lymph node and/or bone marrow biopsy for histology Urine for Bence Jones protein | Pituitary screen Synacthen test Thyroid function tests |
Note: This is not a comprehensive list of investigations to be carried out in every patient with PUO but instead a list of tests that should only be performed when there is a reasonable pretest probability of the condition investigated being present.
ACE = angiotensin converting enzyme; ANA = anti-nuclear antibodies; ANCA = antineutrophil cytoplasmic antibody; Anti-CCP: anti-cyclic citrullinated peptide; CT = computed tomography; LDH = lactate dehydrogenase; MR(I) = magnetic resonance (imaging); OCP = ova, cysts and parasites; PET-CT = positron emission tomography–computed tomography; PCR = polymerase chain reaction; RDT = rapid diagnostic test; TB = tuberculosis; TOE = transoesophageal echocardiogram