Flashcards in Basic Serologic Laboratory Techniques and Investigation of Innate Immunity Related Disorders (P) Deck (79)
What is immunology?
1) Study of the molecules, cells, organs, and systems responsible for the recognition and disposal of foreign materials (nonself) in our body
2) Study of the body’s response to infectious diseases
3) Study the desirable and undesirable consequences of immune interactions
4) Study of the ways in which the immune system can be advantageously manipulated to protect against or treat disease
What is serology?
1) Study of serum and its immune components
2) Refers to the diagnostic identification of antibodies in the serum
What are serological tests?
These are diagnostic methods that are used to identify antibodies and antigens in a patient's sample
What are the purposes of serological tests?
1) To diagnose infections and autoimmune diseases
2) To check if a person has immunity to certain diseases
3) Determining an individual's blood type
What is serum?
The most frequently encountered specimen (especially in immunology and serology)
How is blood collected?
It is collected aseptically via venipuncture and transferred into a clean, dry, sterile tube
What is the reason why hemolysis should be avoided?
Because it may produce a false positive test (or result)
What should be done to blood for preparation for serologic tests?
Allow the blood to clot at room temperature or at 4 DC and then centrifuge
What should be done to serum in preparation for serologic tests (after clotting)?
It should be promptly separated into another tube without transferring any cellular elements
What type of serum is usually recommended for testing?
Fresh, nonheat inactivated serum
What should be done if testing of sx can't be performed immediately?
1) Serum may be stored between 2 DC and 8 DC for up to 72 hrs
2) Avoid excessive heat and bacterial contamination to the sx
3) Heat coagulates the proteins and bacterial growth alters protein molecules (avoid the sx to be in contact with heat)
4) Sx should not be inactivated
What will happen if serum complement is not inactivated?
It will promote lysis of the RBCs and other types of cells and can produce invalid results
What should be done if there is an additional delay of testing of the serum?
Serum should be frozen at -20 DC or below
What should be done to serum in accordance to other tests?
The serum complement must first be inactivated
What is the sx where most immunologic tests are done?
What are the unaccepted sxs for serologic tests?
1) Lipemic serum sample
2) Hemolyzed serum sample
3) Bacterial contamination (turbid serum)
4) Icteric serum
5) Chylous serum
6) Contamination with alkali or acid
Can icteric serum yield valid results?
Yes, it may yield valid results for some tests but may interfere with others
What are the characteristics of lipemic serum?
Serum that appears milky due to high lipid concentration
What are the characteristics of icteric serum?
Serum that appears yellow to deep yellow due to high bilirubin
What are the characteristics of hemolyzed serum?
Serum that appears reddish due to the hemoglobin released by ruptured RBCs
What are the characteristics of chylous serum?
White, opaque, milky serum due to chyle / lipid (chylomicrons)
Which of the following blood sx is acceptable for serologic testing?
What is inactivation (of complement)?
The process that destroys the complement activity
What are the effects of complement in the serum sx?
1) It interfere with the reactions of certain syphilis tests and complement components (e.g., C1q).
2) It can agglutinate latex particles and cause a false-positive reaction in latex passive agglutination assays.
3) It may also cause lysis of the indicator cells in hemagglutination assays
How to inactivate complement in body fluids?
Complement in body fluids can be inactivated by heating to 56 DC for 30 mins
What should be done if more than 4 hrs has elapsed since inactivation (of complement)?
Sx can be reinactivated by heating it to 56 DC for 10 mins
What is the frequent error that results to lab accidents?
Improper pipetting techniques
Is mouth pipetting acceptable in the lab?
How to operate a (serologic) pipette?
1) After the pipette has been filled above the top graduation mark, removed from the vessel, and held in a vertical position, the meniscus must be adjusted.
2) The pipette should be held so that the calibration mark is at eye level. All readings must be made with the eye at the level of the meniscus
3) The delivery tip is touched to the inside wall of the original vessel, not the liquid, and the meniscus of the liquid in the pipette is eased, or adjusted, down to the calibration mark.
4) Before the measured liquid in the pipette is allowed to drain into the receiving vessel, any liquid adhering to the outside of the pipette must be wiped off with a clean piece of gauze or tissue