Page 23 - e-CPG-SLE-8_5_24

Management of Systemic Lupus Erythematosus

The 2012 American College of Rheumatology (ACR) guidelines state
that findings for LN are: 18
 persistent proteinuria >0.5 in UPCR or >0.5 g/day in 24hUP or
urine dipstick ≥3+
 active urinary sediment (defined as >5 red blood cells [RBCs]
per high power field [hpf]; >5 white blood cells [WBCs]/hpf in
the absence of infection or cellular casts limited to RBC or WBC
casts)

• Liver function tests
The standard liver function test (LFT) includes measurement of
transaminases and serum albumin. Liver involvement in SLE is relatively
rare and deranged LFTs can be due to a wide variety of aetiologies
including lupus hepatitis or secondary to co-morbidities e.g. fatty liver
or viral hepatitis. 19, level II-2 Hypoalbuminemia in SLE is associated with
disease activity e.g. LN, protein-losing enteropathy and chronic lupus
peritonitis with ascites. 20, level III
• Acute phase reactants
ESR and CRP levels are the most widely used indicators of the acute
phase response to inflammation. ESR is often raised in active SLE but
is not a reliable marker of disease activity as it does not differentiate
between active lupus and infection. CRP is usually normal or slightly
elevated in the presence of serositis or arthritis. A significantly raised
CRP often indicates infection, therefore patients need to be screened
thoroughly for it. 21

• Antinuclear antibodies
Autoantibodies to intracellular antigens, historically known as ANA, are
serological biomarkers that have a central role in the diagnosis and
classification of systemic autoimmune rheumatic diseases.
Testing for ANA should be performed only when there is a high clinical
suspicion of SLE. ANA is present in 95% of SLE patients. Negative
22
test of ANA suggests a low clinical probability of the patients having
SLE. 21
ANA detection can be performed by enzyme-linked immunosorbent
assay (ELISA), indirect immunofluorescence (IIF) and other techniques.
The IIF using HEp-2 substrate is the “gold standard” for primary ANA
detection because of its overall high sensitivity. ELISA technique is
22
less sensitive than IIF, but it has the advantages of being less laborious,
less subjectivity in its interpretation and can be automated. For these
reasons, ELISA technique is widely used locally; however IIF may be
used for confirmation when indicated.

6