The lupus diagnostic tools of a medical
professional can be divided into three major parts:
- Medical history
- Complete physical examination
- Laboratory tests
Your rheumatologist will ask you questions and should do
a physical examination (I would recommend your using a pain diary or journal to help your doctor understand your symptom
timeline).
Various test need to be preformed for a diagnosis of Lupus.
A complete blood
count is done to check your level of red cells, white cells,
or platelets, (cells that help control bleeding or clotting.)
If your doctor thinks you may have lupus, other
blood tests will determine if you have types of antibodies found in the blood of almost all people with lupus.
ANA TITER
The immunofluorescent anti-nuclear antibody
(ANA, or FANA): is a test to determine if autoantibodies to nuclei are present in the blood.
ANA reports include a titer (number) and
a pattern.
Titer tells how many times the technician
had to dilute your blood plasma to get a sample free of anti-nuclear antibodies. Each dilution involves doubling the amount
of test fluid. A titer of 1:640 would indicate a greater concentration of anti-nuclear antibodies than a titer of 1:320.
The test can even be weakly positive in
healthy individuals. The majority of these people will never develop any signs of lupus or related conditions. The chances
of a person having a positive ANA test also increases as he or she ages.
So a titer of 1:640 shows a greater concentration
of anti-nuclear antibodies than a titer of 1:320 . A positive titer of between the reference ranges norms of 1:80 and 1:160 is
considered by most laboratory test to be in a normal range.
The ANA titers go up and down during the
course of lupus or a mixed connective tissue diseases and a high or low titer does not mean the disease is active.
You can't determine the severity of disease or disease activity from ANA titer.
ANA PATTERS
The homogeneous (smooth) pattern is
found in a variety of connective tissue diseases (...A heterogeneous group of diseases which tends to affect specialized groups
of tissues, bone or organs. A homogeneous pattern may also be found in
patients taking particular drugs.
The speckled pattern cell can be found in
patients with lupus or connective tissue diseases.
The peripheral (or rim) ANA pattern is found
almost exclusively in SLE.
The nucleolar pattern, a pattern with
a few large spots , is found in patients who have scleroderma. (An autoimmune
disease that affects the blood vessels and connective tissues characterized
by thickening and hardening of the skin.)
An ANA test is not conclusive on its own.
COMPLEMENT
Usually a Complement blood test is
also ordered. Complement proteins are identified by the letter
'C' and a number, the most common complement tests being C3, C4, and
CH50. The classic pathway complement function markers of your immune system
are Complement C3 and C4.
Complement is a blood protein that
destroys bacteria and helps control inflammation. Your doctor is
looking for evidence of a chronic, inflammatory disorder of the immune system.
Complement C4 can be deficient in anywhere
from 11% to 80% in the population with Systemic Lupus Erythematosus compared to 1% of the general population with a C4 deficiency
.
If your blood complement values are4 levels
are low (immune complex processing), AND you also have a positive ANA, weight is added to the diagnosis of lupus.
Low C3 and C4 serum levels in
individuals with a positive ANA could also signify
the presence of lupus nephritis ( kidney disease) to your doctor. Blood
chemistry tests can help determine whether organs are functioning normally.
Other blood tests may be done for
diagnosis and as an aid in following disease activity, so be ready for test then more test.
OTHER TESTS
Erythrocyte sedimation rate (ESR) also known as Sed rate. Usually an elevated
ESR is an indication of inflammation.
Other ususal autoantibody test are the anti-DNA, antiSm, anti
RNP, anti-Ro(SSA, anti-La (SSB) .
Besides blood chemistries you may also have
a urinalysis and there may also be x-rays.
If kidney involvement or discoid (skin) lupus is suspected, a biopsy may be performed where a small
piece of kidney tissue or affected arm tissue is removed and examined.
If the lung involvement is suspected a chest
X-ray may be taken.
An echocardiogram may be done to help determine
any heart involvement.
An EKG or MRI may be done if the brain or
central nervous system is involved or to give an indication of which internal systems may be involved.
NO ONE TEST CAN DIAGNOSE LUPUS!
Lupus is an unpredictable disease.
Signs of the disease appear and disappear, sometimes for no apparent reason. Lupus
is unique. Because lupus assumes so many different forms and is different for each person you may undergo other tests too.
For your doctor to find a correct diagnose takes time and often
more tests!
I'm neither a medical doctor
or an immunopharmacologist this is just my
understanding of those tests.
