Uveitis (looking for a cause)

Laboratory tests

• FBC
• CRP
• Syphilis serology
• HLA-B27 (unexplained unilateral non-granulomatous uveitis)
• Tuberculin skin test (not a laboratory test)
• Chest X-ray (not a laboratory test)
• Serum creatinineif needednon-French guidelineBilateral acute anterior uveitis: tubulointerstitial nephritis and uveitis syndrome (TINU) is among the causes to consider ^[2]. The American Family Physician then asks to look for renal involvement (urine tests, renal function), as ocular signs can precede it ^[3], and Germany measures creatinine in all uveitis ^[4]. For the PNDS, the best test for TINU renal involvement is urinary β2-microglobulin, a second-line test ^[1].
• Urine dipstickif needednon-French guidelineBilateral acute anterior uveitis: tubulointerstitial nephritis and uveitis syndrome (TINU) is among the causes to consider ^[2]. The American Family Physician then asks to look for renal involvement (urine tests, renal function), as ocular signs can precede it ^[3], and Germany measures creatinine in all uveitis ^[4]. For the PNDS, the best test for TINU renal involvement is urinary β2-microglobulin, a second-line test ^[1].
• Not a laboratory test: X-rays, or even MRI, of the spine and sacroiliac joints only in case of inflammatory back pain.

Laboratory tests

• FBC
• CRP
• Serum electrolytes
• Serum creatinine
• Serum calcium
• AST
• ALT
• GGT
• Serum protein electrophoresis
• Angiotensin-converting enzyme (ACE)
• Serum lysozyme (granulomatous or intermediate uveitis)if neededThe PNDS places it in the routine work-up of granulomatous and intermediate uveitis ^[1]; with ACE, it helps the presumptive diagnosis of sarcoid uveitis, but it can also be raised in infectious uveitis ^[2].
• Syphilis serology
• Tuberculin skin test (not a laboratory test)
• IGRA test (QuantiFERON)
• Toxoplasmosis serology (if chorioretinal lesion)if neededSerology useful if there is a chorioretinal lesion ^[1,2].
• Lyme serology (if tick bite, erythema migrans or endemic area)if neededDepending on exposure ^[1]: as a routine, Lyme serology adds nothing (3 to 8% seropositive, 0 to 1% of diagnoses reached) ^[2].
• HIV serology (if risk factor)if neededHIV is among the infectious causes of uveitis ^[1,8]; the “risk factor” condition reflects the authors' opinion.

Urine tests

• Urinary calcium / creatinine ratio, spot sample
• Not a laboratory test: chest X-ray or CT (CT suggested in chronic uveitis).