This week is about....
JENG JENG JENG
SERUM BILIRUBIN~
or at least, testing for bilirubin level in neonatal serum.
As all of us know, babies (especially newborns) have a high probability to be jaundiced. Jaundice during the first 24hrs are usually pathological and are most lkely to be due to either blood group incompatibility or infection. An increase in destruction of RBCs will cause an increase in unconjugated bilirubin, which, in the circulation, will bind to albumin. Once all albumin are fully saturated, the excess unconjugated bilirubin -being lipophillic- can enter the cells. They can also cross the blood brain barrier. There, they can bind to proteins in the brain where it is neurotoxic, and therefore, may result in death or severe mental handicap.
Neonatal jaundice occurs as the liver of the newborns are still incapable of metabolizing the bilirubin. Jaundice in full-term babies usually resolves rapidly. In premature babies, however, the jaundice may be more severe as their liver function is not fully mature.
In the lab I'm attached to, we measure the serum bilirubin using
Wako - Bilirubin Tester II
Analysis Principles:-
Total bilirubin concentration is obtained by measuring the absorbance in the serum. The wavelength is set at 455nm.
Range:-
0 - 1 day 2.0 - 6.0 mg/dL
2 - 5 days 3.9 - 6.0 mg/dL
5 - 127 days 0.3 - 1.7 mg/dL
Specimen:- 
2 fully filled heparinized capillary tubes
Equipment:-
Wako-bilirubin Tester II
Centrifuge (3500 rpm/min, 10minutes)
Procedure:-
- Turn power to ON position & allow 10minutes for lamp to stabilize (Temperature control procedure).
- Pull out the cell holder and insert a capillary tube (containing distilled water) in front of the slit. Push the cell holder back into the bilirubin tester.
- Turn the ANA-SET change-over switch to the SET position.
- Set the Digital Display to ZERO by adjusting the Zero-adjustment control for the 455nm (Filter Selection Lever in the upper position).
- Using the left hand, push down & hold the Filter Selection Lever in the 575nm (lower position). Set the Digital Display to ZERO by adjusting the zero-adjustment control for 575nm with the right hand.
- Release the Filter Selection Lever and allow it to return to 455nm position.
- Pull out the cell holder and set the Digital Display to the standard value by adjusting the Span-adjustment control.
- Turn the AVA-SET chenge-over switch to the ANA position.
- Insert a capillary tube filled with sample (already centrifuged) into the cell holder.
- Push down & hold the Filter Selection Lever into the 575nm posititon. Confirm that the Digital Display at ZERO, then allow level to return back to 455nm position.
- Read the Digital Display & read results.
- To measure subsequent samples, repeat steps 9 - 11.
All pictures taken with permission from supervisor.
So, there you go. Seems complicated, but very simple really. Any doubts, feel free to ask =)
Enjoy your SIPs people!!!!
Enjoy your SIPs people!!!!
Name: Mayafirhana
Class: TG02
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12 comments:
Psst..
Why must the cappilary tube contain distilled water?
Andika Putra
TG01
Hi Maya,
3 quick questions for you:
1)What do you meant by
Range:-
0 - 1 day 2.0 - 6.0 mg/dL
2 - 5 days 3.9 - 6.0 mg/dL
5 - 127 days 0.3 - 1.7 mg/dL
2)Why should the 575nm position return to 455nm position? Why should the wavelength be set at 455nm?
3)"Jaundice during the first 24hrs are usually pathological and are most lkely to be due to either blood group incompatibility or infection."
-Why is jaundice during the first 24hrs are usually pathological?
-What is the underlying infection you are refering to?
Thankz!
Han Yang
TG01
Hi,
I am just wondering, are there any quality control that your lab does when operating the Wako? If so, how is it done and how often.
Thanks
Xin Yi
TG02
Hi Maya,
Upon reading your entry, i have 2 questions to ask
1) Why is the wavelenth set at 455nm (the principles behind it)
2) What range of values produce by the Bilirubin tester indicate jaundice in babies? What is the reference range of bilirubin levels in babies that is normal?
Thanks
From: Benjamin Ms
Class: tg01
0606181F
to andika
the cappilary tube containing distilled water is considered a blank. its used in calibration of the bilirubin tester, where its like setting the standard to zero, as there's no interference in distilled water.
to han yang
1st question:
the range is the reference value. it shows the normal bilirubin levels in babies for the different ages (in days).
2nd question:
the 575nm is the wavelength for hemoglobin. so by setting it to zero, it is to get rid of any interference that will affect the measurement of the bilirubin.
455nm is the wavelength to measure the bilirubin level in the serum.
3rd question:
jaundice in the 1st 24hrs of a newborn is usually the most critical as it is too early for the doctor to determine the cause of tha jaundice. if the baby is not monitored closely, it can cause neonatal death, especially in babies with severe jaundice.
an example of an infection is Hepatitis which can be passed down from mother to baby. hepatitis affects the liver and in turn, decrease the baby's ability to metabolize the bilirubin presented to it
to xin yi
of coz QC has to be done. QC must be done at the start of the day when the machine is swtched on, before any samples are run.
they use commercial serum that already has a standard value. they will run the serum as any other samples and make sure that the value obtained is of the same value for the commercial serum.
hi maya,
may i know why need to use heparinized capillary tubes for bilirubin? thanks.
Malerie
TG02
Hi Maya!
You mentioned that "Total bilirubin concentration is obtained by measuring the absorbance in the serum. The wavelength is set at 455nm."
Might i ask if 455nm is the optimum wavelength for the detecting of bilirubin, meaning to say that at that bilirubin absorbs the most amount of light at that wavelength? Also, is it possible for other substances in blood to interfere with the result (for example, high levels of WBC for instance might give a false result of high levels of bilirubin)
Thanks!
Alexander Soo TG02
0608122H
to benjamin
1st question:
i suppose 455nm is set as it is the optimum wavelength that is most absorbed by the bilirubin.
do yew mean the principles behind spectrometometry?
if so, here it is.
a beam of light consisting of photons will be shine through the sample. then the photons encounter the bilirubiin in the sample, it will be absorbed. this reduces the intensity of the light. the amount of light that is passes the sample is measured by the detector to give the value that is seeked.
2nd question:
the normal range of bilirubin levels in babies are aready stated in the range, on my main post. read it up again =)
the bilirubin tester will show the real value of the bilirubin level in the serum. there is no need for any calculations. so to determine is the baby is jaundiced, we refer to the reference range.
to alex
i suppose 455nm is the optimum wavelength. if not, they wouldn't be using it right?
there can be interference in the sample which will disrupt the measurement of the bilirubin. hemoglobin. that is why in calibration of thee machine, we zero-ed out at the 575nm, as 575nm is the wavelength for hemoglobin. this is done so that any hemoglobin in the sample will not be of interference.
i don't think WBC will be of any problem as the sample has already been centrifuged. so all cells should have been collected at the bottom of the cappilary tube.
hey malerie
many apologies for the super long reply. i didn realise your question. heh
anyways, they needed to use heparinised tubes to prevent the clotting of blood in the tube. they didn used edta blood whatsoever, coz perhaps they contains certain chemical which could affect the reading of the results.
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