Uveitis laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Tarek Nafee, M.D. [2]Basir Gill, M.B.B.S, M.D.[3]

Patients with a first episode of unilateral anterior uveitis, without signs or risk factors for infection and without systemic symptoms suggestive of autoimmune disease (e.g., joint pain, skin rash), do not require additional testing. Patients with recurrent or bilateral anterior uveitis, intermediate uveitis, posterior uveitis, or panuveitis should be tested for infection (e.g., syphilis) and systemic disease (e.g., sarcoidosis).^[1]

The presence of certain non-specific laboratory findings, in the presence of uveitis, may be suggestive of certain underlying causes. Examples of tests that may demonstrate abnormal findings include CBC, ESR, CRP, complete metabolic panel, iron studies, and serology titers.^{[2][3][4][5][6]}

The presence of certain non-specific laboratory findings, in the presence of uveitis, may be suggestive of certain underlying causes. Routine laboratory studies should be correlated with a carefully collected history and a precise physical examination. Routine laboratory tests that may be ordered and their respective findings include:^{[2][3][4][5][6]}

Principles of testing

There is no international consensus on the best diagnostic approach for uveitis. Testing varies by regional infection prevalence, comorbidities, immunocompromise, and clinical presentation. Immunocompromised patients, especially those with HIV-related and opportunistic infections, including cytomegalovirus and candida.^[1]

• A low hemoglobin or hematocrit with microcytosis or marginal normocytosis may be indicative of blood loss by inflammatory bowel disease, or any chronic inflammatory disorder.
• Eosinophilia may be suggestive of underlying parasitic infections, or sarcoidosis.
• Elevated white blood cells with a left shift may be suggestive of an underlying infection.
• Decreased white blood cell count may be indicative of an immunosuppressed state.

• Elevated ESR and CRP may be suggestive of an underlying infection or inflammatory condition.

• Low ferritin with a high TIBC is suggestive of chronic blood loss by inflammatory bowel disease.
• High ferritin may be suggestive of anemia of chronic inflammatory conditions.

• Elevated BUN or chromium may be suggestive of renal dysfunction in tubulointerstitial nephritis with uveitis (TINU) syndrome.
• Liver function tests such as AST or ALT may be elevated if sarcoidosis, miliary tuberculosis, or Behcet’s disease affect the liver

• HLA subtyping: HLA-B27, HLA-A29, HLA-B9, HLA-B15
• Antinuclear antibody (ANA)
• Anti-neutrophil cytoplasmic antibody (ANCA)
• Anti-dsDNA
• Toxoplasma or Toxocara IgG or IgM
• Venereal disease research laboratory (VDRL) or Rapid Plasma Reagin (RPR) for syphilis
• Purified protein derivative (PPD) for tuberculosis
• Lyme titer
• HIV test

Ocular Sampling

Aqueous humor and/or vitreous sampling (for microscopy and culture) should be performed if infection is suspected. Infectious organisms are identified in only 22% to 32% of cases, a negative result does not exclude infection. Additional systemic testing, particularly for syphilis or tuberculosis, may still be needed.^[1][7]

• Elevated levels of vitamin D or angiotensin converting enzyme (ACE) are suggestive of sarcoidosis.

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