In this department, it's mostly automated. But it uses only one machine, the great ADVIA Centaur Immunoassay System, by Bayer HealthCare.
Subject title: Immunology
Topic: ADVIA Centaur
Taken from http://www.blockscientific.com/advia-centaur-chemistry-analyzer.htm
The Centaur, as it is affectionately known to all my collegues, is an automated immunoassay analyzer which uses direct chemiluminescence as its principle technique. Chemiluminescence is actually a term to describe the emission of light from a chemical reaction in the sample that is being analyzed.
In the Centaur, acridinium ester (AE) is used as the chemiluminescence label. It was found out that AE is preffered and used as it does not require any addition of catalyst or substrate. It also cause the reaction to occur more rapidly, increase assay sensitivity and allow a longer reagent shelf life due to its dimethyl form.
OK, so in the Centaur, the AE is oxidized by hydrogen peroxide. The acidic environment is changed to basic in order to maximise the amount of light emitted. In this case, oxidation occurs super fast with its peak amount emitted in less than a second. This light is then measured to give the results for the sample that is being analyzed.
The Centaur can analyze for many constituents found in the blood, such as tumour markers ( CA 125, CA 199 ), thyroid stimulating hormone, Hepatitis A & B surface antigens or antibodies, cortisol, ferritin, testosterone, folate, vitamin B12, and many more. The most which is tested is for HIV.
The blood received from various clinics are centrifuged for 10minutes before they are labelled and barcoded. The tests to be done on the sample can either be pre-specified by the LIS or done manually.
Once the tests are selected, they are put in test-tube racks before they are inserted into the machine. Once all the samples are taken, the completed test-tube rack are pushed out while the samples are incubated and undergo the various tests. Its as simple as that, and that is done manually.
Those which are controlled by the LIS are just placed in the Sample Manager. The rest are fully automated, from selecting the right test-tube, to allocating the test-tube to the correct Centaur by the transportation track, to doing the various tests on its own, to going back into the Sample Manager after its all done. All the med techs have to do is to make sure everything runs smoothly, and validate the results.
Fantastic machine ain't it?
So that's all for now. Another week to get fully acquainted with the Centaur before I'm posted to another department.
Have fun for all your SIP!!!!
Name: Mayafirhana
Class: TG02
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10 comments:
Hello
May I know what is a sample manager?
Why must the environment be changed to basic in order to maximize the amount of light emitted?
Thanks!
ShiHui
TG02
Hi!
Actually i wanted to know the answers to what fluid collectros asked too. And also, how is the light emitted measured?
Thanks =)
Lyn
TG02
Hi Maya!
Hey im attached to immunology lab for e first week too!
Anyway you mentioned that the tests can either be pre-specified by the LIS or done manually... Can you explain it?
Does it mean the ADVIA Centaur will have a a specific test for each constituent of the blood?
And why must the samples be incubated? For my laboratory we only incubate baby's blood:)
Thanks!
cheers,
huimin
tg01 =)
mya to fluid collectors
a Sample Manager is just like any other ordinary cabinet which stores the test-tubes temporarily, the only difference is that, its automated. there are robotic 'arms' in the sample manager which will pick out a particular test-tube from its barcode. the test-tube selection is controlled by the captain.
about the environment being changed to basic, is just to maximize the amount of light emitted. if not, there will be very little photons (light energy) to be measured. its very mechanism is not really known. apologies if it doesn't answer your question.
mya to codec 5
the light emitted from within the Centaur is measured by this device called the photomultiplier tube.
it is an effective photon counter which can detect very low level of light which is emmitted from the chemical reaction in the Centaur.
the principle of this technology is very advance, if i may say. but in short, the light enters photomultiplier tube, gets detected and produce an output signal.
hope i manage to answer your question.
mya to sip
what i mean by pre-specified is that according to the barcode label on the specimen, the specimen already has a particular test to be done, eg HIV test. so all the med techs have to do is insert the tube into the Centaur. the Centaur will read the barcode, understands that it has to run the HIV test, before carrying out the actual test.
what i mean by manually is that, the med techs go to the computer attached with the Centaur n MANUALLY enter the test that the specimen has to go through, before inserting it into the Centaur.
yew understand so far? if not, i can help elaborate further.
anyway, different Centaurs are programmed to run different tests. Example:
-one Centaur runs tumour markers, HIV and rubella IgG tests.
-another Centaur runs HIV, Vitamin B12, folate, cortisol tests.
-another run mostly hormone tests. so yes, different Centaurs tests for different constituents of the blood.
in Centaur, it is required to incubate the samples. coz it is during this icubation period where the labelled Ag/Ab binds to the target Ab/Ag. this requires time, so i was told.
Hi Maya!
Out of curosity, are there any disadvantages for using acridinium ester as a chemiluminescence label as compared to other options out there?
Thks!
Alexander Soo, TG02
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- Murk
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