Renal immunology blood tests
This is the battery of blood tests that are usually done on patients with suspected glomerulonephritis – and what they are looking for.
None are completely reliable, i.e. if they are positive/negative, the test does not fully diagnose/exclude the disease.
A renal biopsy is almost always required to be certain of the diagnosis.
- Anti-nuclear antibody (ANA). Positive in systemic lupus erythematosus (SLE, lupus)
- Double-stranded DNA (DsDNA). Positive in SLE
- Anti-neutrophil cytoplasmic antibody (ANCA; with PR3 and MPO subtypes). Positive in some types of vasculitis
- Anti-glomerular basement membrane (anti-GBM) antibody. This attacks the basement membrane of the kidneys and lungs. They are a cause of anti-GBM disease, also known as Goodpasture’s disease
- Complement C3/4. C3 low in:
- SLE
- Dense deposit disease (DDD, formerly mesangiocapillary type II)
- C3 glomerulonephropathy (C3GN, formerly mesangiocapillary type I or III)
- Post-infectious glomerulonephritis
- Immunoglobulins (IgG, A and M). IgA high in 50% people with IgA nephropathy
- Serum electrophoresis. Done looking for an abnormal protein suggestive of myeloma (and other blood disorders)
- Serum free light chains (SFL). Done looking for myeloma (and other blood disorders)
- Anti phospholipase A2 receptor (PLA2R) antibody. Positive in primary membranous nephropathy, one type of chronic glomerulonephritis
- Antistreptolysin O (ASO) antibody – measures antibodies against streptolysin O, a substance produced by group A streptococcus bacteria. Positive in post-infectious glomerulonephritis
- Hepatitis B and C, HIV. Can cause several types of chronic glomerulonephritis.
ANCA antibodies
Anti-neutrophil cytoplasm antibodies (ANCA) are autoantibodies that target a type of white blood cell called a neutrophil.
In ANCA-associated vasculitis, ANCA specifically bind to two proteins that are normally found in the fluid within the neutrophil (cytoplasm). The two proteins are called proteinase 3 (PR3) and myeloperoxidase (MPO).
Patients with ANCA-associated vasculitis usually have autoantibodies against PR3 (PR3-ANCA) or MPO (MPO-ANCA) but not both.
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