Diagnosis of SLE
History and Examination
In the presence of a typical skin rash and arthralgia and positive results from investigations the diagnosis of SLE can be relatively easy.
However, where the symptoms are non-specific and affecting various parts of the body the diagnosis can be very difficult and should be made by a person experienced in the diagnosis and management of this condition.
Investigations
Blood Tests
Blood tests are likely to show the following:
- 80% test positive for antinuclear antibodies (ANA’s - but they may also be present in other diseases).
- SLE patients may have a raised level of Double- Stranded DNA and positive testing for antibodies to double-stranded DNA demonstrates a high likelihood of SLE (but the absence does not exclude it). It can be a useful indicator of disease activity.
- 40% of those with SLE are Rheumatoid Factor positive.
- Other blood tests are necessary to check red blood cells, white blood cells and platelets (to see if there is a reduction in levels).
- More specialised testing is available in some laboratories to help test for the condition.
- Blood tests to identify the presence of antiphospholipid antibody, which may or may not be present.
- Serum creatinine and eGFR (Glomerular Filtration Rate) to assess the level of kidney function. It is raised if kidney function is affected.
Urinalysis
Urine tests are performed to establish the presence of red cells, casts or protein in the urine, which may establish the presence of early kidney disease.
More specialist investigation would involve a 24-hour urine collection.
Click the link for details of:
Amended November 2008
