Case 1: Diagnostic Testing

Case 1 Index

Take a look at some initial diagnostic testing below.
Urinalysis/microscopy, urine electrolytes
Urine sediment
Basic labs
Kidney Ultrasound

Basic Lab Ref

Has your differential diagnosis changed? Choose your top 3 before moving on to additional testing!
Post-infectious glomerulonephritis (PIGN)
Membranous nephropathy
Diabetic nephropathy
Acute interstitial nephritis (AIN)
Systemic lupus erythematosus (SLE) nephritis
Anti-glomerular basement membrane (GBM) disease
Acute tubular necrosis (ATN)
IgA nephropathy


Choose the 3 highest yield diagnostic tests below!
Complement levels (C3, C4)
Excellent choice, we should look for complement-mediated diseases in patients like this one with nephritic syndrome. C3 5 mg/dL (ref: 90 – 180 mg/dL); C4 10 mg/dL (ref: 10 – 40 mg/dL)
HIV nephropathy is more likely to present with a nephrotic rather than nephritic syndrome, so this may be a low yield test. Try another test!
Repeat Hemoglobin A1C
Diabetic nephropathy is unlikely to present with hematuria, as our patient has here. Try again!
Anti-glomerular basement membrane antibody
You call the lab, and the result for this test is still not ready. We’ll have to move on for now and try another test.
Anti-nuclear antibody (ANA)
1:80 (reference: less than 1:80)
Serum protein electrophoresis and free light chains
Patients with monoclonal gammopathies and kidney disease usually present with nephrotic range proteinuria and nephrotic syndrome – this is a low yield test at this time. Choose another test!

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Case 1 Index
Case 1 Introduction
Case 1 Physical Exam