Download Complete blood count in primary care

INTRODUCTION TO
AUTOIMMUNITY AND AUTOANTIBODY TEST
By Madiha Hamid
Horror autotoxicus:
Literally, the horror of
self-toxicity.
Tolerance to self Ags is
maintained by central and
peripheral mechanisms.
Dysregulation in these
mechanisms will trigger
autoimmune disease.
A family of 80 chronic and disabling
diseases
Affects about 15-23 million people in
the USA.
Autoimmunity Genetic Factors
CAUSES
Three main sets of genes are
suspected in many autoimmune
diseases. These genes are related to:
•Immunoglobulins
•T-cell receptors
•The major histocompatibility
complexes (MHC).
Autoimmunity Environmental Factors
Following factors can trigger
autoimmunity:
•Pathogens,
•drugs,
•hormones,
•toxins
Symptoms
Common symptoms may
be Fever, muscle ache,
fatigue, joint pain.
Each disease has specific
symptom
Autoimmunity Can be classified into clusters
that are either organ-specific or systemic
Lungs of a patient
with Goodpasture’s
Autoantibody test
Mainly done for the diagnosis of autoimmune disease.
The Antinuclear antibody (ANA) test is often ordered first. ANA is a marker of the
autoimmune process –
it is positive with a variety of different autoimmune diseases but not specific.
If an ANA test is positive, a panel of 4 or 6 autoantibody tests called extractable nuclear
antigens (ENA) is typically ordered. , it is often followed up with other tests associated
with arthritis and inflammation, such as a rheumatoid factor (RF), an erythrocyte
sedimentation rate (ESR), a C-Reactive Protein (CRP), and/or complement protein
complement levels.
The AMA test is ordered to help diagnose primary biliary cirrhosis (PBC).These abs are
detedtced by indirect immunoflourescence in > 90% of patients.Reference range is <0.1
-1.0 units.
APA testing is used to help determine the cause of :
Inappropriate blood clot formation (unexplained thrombotic episode, excessive clotting)
Recurrent miscarriage
Low platelet count (thrombocytopenia)
Prolonged PTT test
A cyclic citrullinated peptide (CCP) antibody test may be ordered along with or
following a rheumatoid factor (RF) test to help diagnose rheumatoid arthritis (RA) and to
assess the severity and probable course of the disease (prognosis).
C-Reactive Protein
Complement
Levels
Gul Sanober
C-reactive protein (CRP) test
• a non-specific marker produced by the liver
• increases during episodes of acute systemic
inflammation
• measured by blood tests.
• Some forms of arthritis
• Autoimmune diseases, such
as lupus or vasculitis
• a CRP level of 10 mg/L or lower is considered
"normal."
Complement Levels
• most commonly C3 and C4
• Synthesized in the liver
• Measured through blood tests
• Normal levels
C3
– Males: 88-252 mg/dL
– Females: 88-206 mg/Dl
C4
– Males: 12-72 mg/dL
– Females: 13-75 mg/dL
• Levels decrease in autoimmune
disorders(Hypocomplementemia)
• Diagnose and monitor:
1. acute or chronic autoimmune diseases such
assystemic lupus erythematosus (SLE)
2. immune complex-related diseases and conditions
such as glomerulonephritis, serum
sickness, rheumatoid arthritis, and vasculitis
• Individual complement components ordered when
the total complement activity (CH50 or CH100) is
abnormal to help determine which of the
component(C1 to C9)s are deficient or abnormal
Considerations
• Serum is preferred
• All samples must show no signs of
deterioration and lipaemic samples should be
avoided.
• Samples may be stored at 4°C prior to analysis
• Acute malarial infection can cause false-positive
results
• Complement component 3 has been shown
to interact with Factor H.
Rheumatoid factor - RF
By: Namra Haq
Rheumatoid factor explained
Rheumatoid factor is an immunoglobulin (antibody) which can bind to other
antibodies. Antibodies are normal proteins found in the blood which
function within the immune system. Rheumatoid factor though is not
normally found in the general population (only found in about 1-2% of
healthy people). The incidence of rheumatoid factor increases with age
and about 20% of people over 65 years old have an elevated rheumatoid
factor.
A blood test is used to detect the presence of rheumatoid factor. The blood
test is commonly ordered to diagnose rheumatoid arthritis. Rheumatoid
factor is present in 80% of adults who have rheumatoid arthritis but there is
a much lower prevalence in juvenile rheumatoid arthritis. The incidence of
rheumatoid factor increases with duration of disease in rheumatoid
arthritis: at 3 months the incidence is 33%, while at one year it is 75%. Up
to 20% of rheumatoid arthritis patients remain negative for rheumatoid
factor (also known as "seronegative rheumatoid arthritis") throughout the
course of their disease.
Other conditions in which RH is positive
apart from rheumatoid arthritis
Other autoimmune diseases can also be positive rheumatoid factor
including:
Sjogren’s Syndrome, Systemic Lupus Erythematosus, Scleroderma,
Polymyositis, Dermatomyositis, Mixed Connective Tissue Disease
Other infections or conditions which can be associated with positive
rheumatoid factor include:
Bacterial Endocarditis, Osteomyelitis, Tuberculosis, Syphilis, Hepatitis,
Mononucleosis, Liver Cirrhosis, etc.
Conditions not associated with RF
Rheumatic conditions NOT associated with elevated rheumatoid factor
include:
Osteoarthritis, Gout, Reiter's syndrome / Reactive arthritis, etc.
How is RF factor measured?
The amount of rheumatoid factor in blood can be measured by:
Agglutination tests
One method mixes the patient's blood with tiny latex beads covered
with human antibodies (IgG). The latex beads clump or agglutinate if
rheumatoid factor (IgM RF) is present. Another method mixes the
patient's blood with sheep red blood cells that have been covered with
rabbit antibodies. The red blood cells clump if rheumatoid factor is
present.
A titer is an indicator of how much the agglutination test blood sample
can be diluted before rheumatoid factor is undetectable. A titer of 1:20
indicates that rheumatoid factor can be detected when 1 part of blood
is diluted by up to 20 parts saline. The lab value for rheumatoid factor
of 1:20 or less is considered normal.
Nephlometry test
This method mixes the patient's blood with antibodies that cause the
blood to clump if rheumatoid factor is present. A light is passed through
the tube containing the mixture and an instrument measures how much
light is blocked by the mixture. Higher levels of rheumatoid factor create a
more cloudy sample and allow less light to pass through, measured in
units. The lab value for rheumatoid factor of 23 or less units is considered
normal.
When analyzing lab results the following should be considered:
•A rheumatoid factor more than 23 units and a titer more than 1:80 is
indicative of rheumatoid arthritis but may also occur in other conditions.
•False positive results can occur when the blood is high in fats.
•Inaccurate results can be caused by improper handling of the blood
specimen.
•A negative test result for rheumatoid factor does not exclude the
diagnosis of rheumatoid arthritis.
 Marker of Inflammation-autoimmune diseases like lupus or
rheumatoid arthritis cause inflammation.
 Nonspecific Test
 Not used for screening purpose (low senstivity and specificity)
 Inexpensive
• Uses:
a. Diagnosis(auto-immune diseases ,rheumatoid arthritis, chronic
kidney diseases)
b. Disease severity
c. Monitoring response to therapy ( inflammatory diseases such as
temporal arteritis, polymyalgia rheumatica and rheumatoid
arthritis)
Measure of the
settling of red blood
cells in a tube of blood
during one hour.
When
abnormal
proteins are present
in the blood, typically
due to inflammation
or infection, they
cause red blood cells
to clump together and
sink more quickly.
Autoimmune Disorders
Very high ESR levels
Allergic vasculitis
Giant cell arteritis
Polymyalgia rheumatica
Higher than Normal
Factors That May Influence ESR
Reference Age
Adults Upper limit of reference range (mm/hr)
Increase ESR
Age < 50 years
•Old Age
Men
0 to 15
•Pregnancy
Women 0 to 20
•Anemia
Age > 50 years
•Macrocytosis
Men
0 to 20
Women 0 to 30
Decreased ESR
•Extreme leukocytosis
•Polycythemia
•Red blood cell abnormalities
Secret Blood Test of Autoimmune
Disease
TH1 / TH2 Cytokine Test
The immune system works like a seesaw. On
one side you have Th1 cytokines that initiate the
first line of defense. On the other side you have
Th2 cytokines which help product antibodies to
protect you from future invasions. However,
when one side goes up, the other side goes
down. This can contribute to a weak immune
system and potentially promote autoimmune
conditions.
Complete blood count in primary
care
PRINCIPLE
• This test measures red blood cells and white
cells. The test includes: red blood cell count,
hemoglobin, hematocrit, MCV, MCHC, RDW,
platelet count, white blood cell count,
neutrophils, lymphocytes, monocytes,
eosinophils and basophils.
Phisiology:
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Whole blood collected in EDTA (purple top tube) is the only acceptable
specimen. The
specimen must be kept and transported at room temperature. For best
results, the
collection tube should be full and no less than half full. Mix the
specimen slowly for 2
minutes.
Unacceptable specimens include:
Any sample not collected in an EDTA tube.
Any tube less than half full
Any tube that is not labeled properly
Hemolyzed specimens
Specimens older than 24 hours
Specimens that are clotted
METHOD: VCS Technology, Hemoglobinometry
Significance:
•Screen for a wide range of conditions and diseases
•Help diagnose various conditions, such as anemia, infection,
inflammation, bleeding disorder or leukemia, to name just a few
•Monitor the condition and/or effectiveness of treatment after a
diagnosis is established
•Monitor treatment that is known to affect blood cells, such as
chemotherapy or radiation therapy
•A CBC is a panel of tests that evaluates the three types of cells
that circulate in the blood and includes the following:
a.Evaluation of white blood cells, the cells that are part of the
body's defense system against infections and cancer and also play
a role in allergies and inflammation
b.Evaluation of red blood cells, the cells that transport oxygen
throughout the body
c.Evaluation of platelets, cell fragments that are vital for normal
blood clotting
• >20,000 Hertz OR more
• Diagnostic Medical Ultrasound - use of high frequency sound waves
to aid in the diagnosis and treatment
• Frequency ranges -> 2 - 15 MHz
• Piezoelectric Effect : The principle of converting energy by applying
pressure to a crystal
• Pulse-echo principle, ultrasound transducers; [convert 1 type of
energy to another]
– Electricity into sound = pulse {machine to tissue}
– Sound into electricity = echo {tissue to machine}
• Echoes are interpreted and processed by the ultrasound machine
•
Digital Radiography, High Frequency Radiography Unit help in diagnosis
•
Electro magnetic radiations {ELECTRONS}
•
High-speed flow of electrons bombarding the anode target surface, 99% converted
to heat, to produce X-ray - 1% ; {(50Hz or 60Hz)}
•
Useful in detection of pathology of the skeletal system
•
Bones contain much calcium hence absorb x-rays efficiently ; reduces amount of Xrays reaching detector in the shadow of the bones {making them clearly visible on
the radiograph}
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In medical diagnostic applications, low energy (soft) X-rays are unwanted {since they
are totally absorbed by the body, increasing the radiation dose without contributing
to the image}
•
A thin metal sheet, often of “aluminium”, [an X-ray filter], usually placed over the
window of the X-ray tube, absorbing the low energy rays. Center of the spectrum
shifts toward higher energy {hardening the beam ; Hard X-rays}
•
Medical test performed by surgeon involving sampling of cells or tissues for examination.
[TISSUE SAMPLING]
•
Medical removal of tissue from a living subject to determine the presence or extent of a disease.
•
Frequent biopsies are taken to assess activity of disease and to assess changes that precede
malignancy.
•
Examined under a microscope or analyzed chemically by a pathologist.
•
Entire lump or suspicious area is removed {Excisional biopsy}.
•
Sample of tissue is removed with preservation of the histological architecture of the tissue’s
cells {Incisional biopsy or core biopsy}.
•
Scanner's images help doctors determine exact position of the needle in the targeted tissue
{CT-guided biopsy}.
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An ultrasound scanner helps a doctor direct the needle into the lesion. {Ultrasound-guided
biopsy}.
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A needle withdraws material out of a mass. {Aspiration biopsy}.