Serological Testing Flashcards
What type of test is RPR?
Non-treponemal test for serologic detection of the antibody Reagin.
It is a screening test.
Why is Reagin produced?
It is produced in response to an infection of syphilis caused by Treponema pallidum.
Reagin is a phospholipid that acts like an antigen.
It is found in the serum/plasma of patients with syphilis.
What must be done when an RPR test is reactive?
Confirmation via a Fluorescent Treponemal Antibody-absorbed Test (FTA-ABS)
What is present in a reactive RPR test?
Flocculation
For the FTA-ABS test, what two substances are placed onto the slide?
Dead T. pallidum and the patient’s serum.
If antibody is present in the serum of a patient infected with syphilis, what substance is added to detect the antibody?
Fluorescein-labeled anti-human globulin
How do you prepare serum or plasma samples for RPR testing?
Collect venous blood in tubes
- Serum: tubes without anticoagulant (red/SST)
- Plasma: tubes with anticoagulant (purple)
After centrifugation, serum should be clear and non-hemolyzed.
How do you mix the antigen suspension for RPR testing?
Vigorously for 10-15 seconds.
How many drops of specimen and antigen are dispensed onto the RPR testing card?
1 drop of specimen, then spread it around the circle
1 drop of antigen to each specimen and controls
How long do you place the RPR test card on the rotator, and at what speed?
8 minutes at 100rpm
How do you help differentiate non-reactive results from weakly active results in the RPR test?
Rotate and tilt the card by hand 3-4 times “to and fro”
How do you examine the RPR test card to read results?
Macroscopically under a high intensity lamp or strong daylight.
Reactive RPR test results shows flocculation ranging from:
Slight but definite.
Minimum to moderate.
Marked and intense.
What should be run with every batch of RPR tests to ensure accuracy and reliability of test results?
RPR Quality Controls.
RPR Quality Control starts with what?
Proper collection and handling of specimen.
Assaying control reagents.
Checking instrument performance.
- Calibrate rotator to 100 rpm.
- Calibrate antigen needle to 60 drops per 1mL.
What control reagents do you use for the RPR test?
Reactive, weak-reactive and non-reactive controls.
What is run every time an unknown RPR sample is tested?
Control reagents, which are treated like patients.
What is a self-limiting disease caused by the Epstein-Barr virus?
What is its typical population?
Infectious Mononucleosis.
Typically seen in young adults and children <5 years.
What are the signs and symptoms of mono?
Fever, malaise, lethargy, sore throat with exudates, enlarged lymph nodes on the neck, mild hepatitis, enlarged spleen, blotchy skin.
Mono causes the accumulation of increased numbers and abnormal forms of lymphocytes and monocytes in the lymph nodes, causing the formation of what antibody?
Heterophile Antibody
It is structurally similar to the antibody that is specifically produced as a response to antigen stimulation.
What type of serum sample will you collect for the Monospot test?
Venous blood with or without anticoagulant.
After centrifugation it should be clear and non-hemolyzed.
How soon can you test the Monospot specimen?
Within 24 hours of blood collection of stored between 2-8 C.
How do you disperse and suspend the latex particles in the buffer solution of the monospot test?
Gently for 10-15 seconds. Do not shake vigorously.
How many drops of specimen and latex reagent do you add to the monospot test?
1 of each, then mix together with stirrer.
