For this sharing, I will talk more about immunoassay section. I will be sharing some guideline on HIV screening & confirmation tests and BDvacutainer uses.
In the immunoassay section, the analyser use is the Architect ci2000. This machines uses the chemiluminescent microparticle immunoassay technololgy to determine the presence of Ag, Ab and analytes in the sample.
The BDVacutainer System
Cap Colour: Red
Additives: None
Effects on Specimen: Blood clots, and the serum is separated by centrifugation
Uses: Chemistries, Immunology and Serology, Blood Bank (Crossmatch)
Cap Colour: Gold
Additives: Separating gel and clot activator
Effects on Specimen: Serum separator tube (SST) contains a gel at the bottom to separate blood from serum on centrifugation
Uses: Serology, endocrine, immunology, including HIV
Cap Colour: Light green
Additives: Plasma Separating Tube (Na Heparin)
Effects on Specimen: Anticoagulants with lithium heparin; Plasma is separated with PST gel at the bottom of the tube
Uses: Chemistries
Cap Colour: Lavender/Purple
Additives: EDTA (liquid form)
Effects on Specimen: Forms calcium salts to remove calcium to prevent clotting and platelet clumping
Uses: Hematology
Cap Colour: Light blue
Additives: Sodium citrate (Na Citrate)
Effects on Specimen: Forms calcium salts to remove calcium
Uses: Coagulation tests (PT, PTT)
Cap Colour: Dark green
Additives: Sodium heparin or lithium heparin
Effects on Specimen: Inactivates thrombin and thromboplastin
Uses: Ammonia, lactate, HLA typing
Cap Colour: Dark Blue
Additives: Sodium heparin
Effects on Specimen: Forms calcium salts. Tube is designed to contain no contaminating metals
Uses: Toxicology and trace element testing (zinc, copper, lead, mercury) and drug level testing
Cap Colour: Light Gray
Additives: Sodium fluoride and potassium oxalate
Effects on Specimen: Antiglycolytic agent preserves glucose
Uses: For lithium level, use sodium heparin. Glucose test.
HIV Screen: Reactive
HIV Ab Confirmation: Indeterminate
Interpretation: This reactivity pattern commonly occurs in uninfected individuals due to the presence of non-specific Ab but may also be observed in early HIV infection. If exposure to HIV is suspected, 10ml blood in EDTA is send in 2-4 weeks time for repeat screening. Otherwise, another serum sample taken 6 weekslater will permit diagnosis in the majority cases.
Note: If a second sample is taken after 6 weeks and the western blot remain unchanged(still indeterminate), the following will be the interpretation applies:
- This indeterminate western blot profile has remain unchanged over 6 weeks. This may indicate a negative HIV Ab status associated with the lack of clinical signs and symptoms and/or supported by a negative history of exposure. If repeated exposure is suspected after the first sample is collected, send another sample for repeating screening.
HIV Screening: Reactive
HIV Ab Confirmation: Inconclusive
Interpretation: This is an indeterminate profile that include Ab to envelope and/or polymerase genes, which one often more sensitive indicators of earlu seroconversion. This profile may however also be due to non-specific Ab. 10ml blood in EDTA is send in 2-4weeks time to resolve the result.
HIV Screening: Reactive
HIV Ab Confirmation: Positive
Interpretation: Patient is consider HIV Ab positive
To confirm whether HIV positive or negative take a long procedure. And HIV Ab confirmation is negative does not mean negative too. As to test for HIV Ab confirmation take a period of time after exposure.
Feel free to ask qn but pls be mercy.
Juexiu Tg02
4 comments:
Hey Jue Xiu,
Is this ur post? You din put ur name leh. rem to put ar..
Anyway, I want to ask how HIV screening is conducted, what are the steps/procedures involved in the screening? you may tell me briefly on that.. thanks girl..
=)
doreen (tg01)
Hello Juexiu,
You mentioned about the vacutainer system and I would like to ask you how does the blood clot in the red-capped tube if no additives were added? I've also heard about the abbrev. HLA but what exactly is HLA?
Looking forward to your reply. Thank you.
-Alex Tg02
hihi, sorry for the long waiting. I have some problem with my my computer, i couldnt log in to my window. I just got it fix. okay, the following is the ans.
Doreen:
Procedure of HIV screening. The specimen will still go through normal procedure, entry order then to the respective department for testing. The specimen will be tested using architect ci8200.
If is non-reactive does not mean the individual do not have HIV. As HIV have a window period. And if the serum is taken less than 3 months after exposure. the test will be repeated.
If reactive, the sample will be send for HIV Ab confirmation. The sample will be double bag, and one specimen in one bag. The interpretation of the result is in the blog.
Alex:
the red capped tube have no additives, thus the blood will clot. The purpose of the tube is to let the blood clot. Thus to spin down for the serum.
HLA typing is stand for Human Leukocyte Antigen (HLA) typing. It is to determine whether a patient has a suitable donor for stem cell transplant.
When two people share the same HumanLeukocyte Antigens, they are said to be a "match", which is their tissues are immunologically compatible with each other. HLA are proteins that are located on the surface of the white blood cells and other tissues in the body.
There are three general groups of HLA, they are HLA-A,HLA-B and HLA-DR. There are many different specific HLA proteins within each of these three groups.
Each of these HLA has a different numerical designation, for example, you may have HLA-A1, while some one else might have HLA-A2.
Hope that you could understand, if not feel free to ask. (n_n)
Juexiu
TG02
hihi, sorry for the long waiting. I have some problem with my my computer, i couldnt log in to my window. I just got it fix. okay, the following is the ans.
Doreen:
Procedure of HIV screening. The specimen will still go through normal procedure, entry order then to the respective department for testing. The specimen will be tested using architect ci8200.
If is non-reactive does not mean the individual do not have HIV. As HIV have a window period. And if the serum is taken less than 3 months after exposure. the test will be repeated.
If reactive, the sample will be send for HIV Ab confirmation. The sample will be double bag, and one specimen in one bag. The interpretation of the result is in the blog.
Alex:
the red capped tube have no additives, thus the blood will clot. The purpose of the tube is to let the blood clot. Thus to spin down for the serum.
HLA typing is stand for Human Leukocyte Antigen (HLA) typing. It is to determine whether a patient has a suitable donor for stem cell transplant.
When two people share the same HumanLeukocyte Antigens, they are said to be a "match", which is their tissues are immunologically compatible with each other. HLA are proteins that are located on the surface of the white blood cells and other tissues in the body.
There are three general groups of HLA, they are HLA-A,HLA-B and HLA-DR. There are many different specific HLA proteins within each of these three groups.
Each of these HLA has a different numerical designation, for example, you may have HLA-A1, while some one else might have HLA-A2.
Hope that you could understand, if not feel free to ask. (n_n)
Juexiu
TG02
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