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Blood Bilirubin
Blood Bilirubin
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Blood Bilirubin
Category: Proteins, protein metabolites and pigments.
Subcategory: Pigments.
Material studied: Blood.
Estimated cost of test: $6.50.
Patient time for test: 5-10 minutes.
Reliability of test results: Good.
Available as home self-test? No.
Note: Test evaluates liver function and the condition of red blood cells. It is valuable when performed on newborns because elevated unconjugated bilirubin can accumulate in a newborn's brain and cause irreparable tissue damage.
BEFORE THE TEST
Purpose of test:
Evaluates liver function.
Diagnoses jaundice*.
Monitors progression of jaundice*.
Helps confirm diagnosis of obstruction of the bile ducts.
Helps diagnose cause of anemia*.
Determines whether a newborn requires a transfusion or phototherapy* when infant has a dangerously high bilirubin level.
Where is test performed?
Commercial laboratory, hospital, doctor's office.
Who performs test?
Lab technician, nurse, doctor.
Risks and precautions:
If tourniquet is applied on the arm too long (over 1 minute), it may cause an inaccurate test result. Request another sample to be collected to ensure accuracy.
Patient preparation:
Activity--No changes necessary.
Diet--Don't eat any food or drink any liquid for at least 12 hours before the test. Fasting is not necessary for a newborn.
Medicines--Inform the person performing the test if you have recently taken any medications listed under Taking these drugs may affect test results. You may be asked not to take this medication before the test.
Disrobing--None required. Roll up sleeve only.
THE TEST
Sensory factors:
Touching--You will feel mild discomfort when the needle is inserted into the vein or when the lancet pricks a finger, heel or ear lobe.
Seeing--You will see the technician, nurse or doctor, the basket or tray to hold the equipment, the needles, syringes, collecting tubes and bandages.
Feeling--Some degree of apprehension or fear is normal and should be expected. Discomfort disappears when the test is finished.
Other senses (taste, smell, hearing)--Not affected.
Equipment used:
Needles, syringes and heparinized* collecting tubes. Sterile, disposable equipment prevents contamination or spread of infection. There is no risk of becoming infected with the hepatitis virus, AIDS virus or any other infecting germ.
Description of test for a newborn:
Usually a small amount of blood is drawn from the infant's heel. This procedure is safe and quickly performed.
Skin over the selected site is cleaned with an antiseptic.
The operator quickly pierces the skin to a shallow depth, using a sterile, disposable metal lancet. The drop or two of blood produced is collected into a capillary pipette.
Description of test for an adult:
Technician, doctor or nurse applies a tourniquet or blood-pressure cuff to the upper arm if blood is collected from a vein.
Skin over the vein to be stuck is cleaned with alcohol or other antiseptic on a piece of cotton.
When blood is drawn from a vein, the operator feels the vein to be used then punctures both the skin and vein in one quick stroke. The needle used is a sterile, disposable needle attached to a sterile, disposable syringe.
Operator withdraws the needle and transfers sample from the collecting syringe into sterile tubes (identified with your name) before sending samples to the laboratory for analysis. Tubes are treated with an anti-coagulant chemical to prevent clotting.
AFTER THE TEST
Immediate post-test care:
Apply pressure to the puncture site with cotton provided by the laboratory.
If a vein has been punctured, raise your entire arm over your head while applying pressure.
Some discoloration, soreness or swelling may develop at the venepuncture site. This responds well to moist, warm compresses applied every 2 to 4 hours.
Activity after test:
Resume taking any medications that were withheld before the test.
Return to pretest activities right away.
Use warm compresses if blood collects under the puncture site or if the area becomes tender, red or painful.
Time before test results available:
Test requires only a few minutes in the laboratory. Time before results are reported to the doctor or patient varies from a few minutes to a few days.
TEST RESULTS
Test values: Test results are determined by spectrophotometry*.
Normal values:
Adult indirect bilirubin levels--1.1 mg/dl or less.
Adult direct bilirubin levels--Less than 0.5mg/dl.
Total bilirubin in a newborn--1 to 12mg/dl.
What HIGH or INCREASED may indicate:
Congenital enzyme deficiencies (Gilbert's disease*).
Liver damage.
Severe hemolytic anemia*.
Obstruction of bile ducts from stones* or tumors*.
If over 20mg/dl in a newborn, exchange transfusion may be needed.
Taking these drugs may affect test results:
Aminophenol.
Anti-malarials.
Ascorbic acid.
Dextran.
Epinephrine.
Ethoxazene.
Histidine.
Indican.
Isoproterenol.
Levodopa.
Methyldopa.
Novobiocin.
Phenazopyridine.
Phenelzine.
Primaquine.
Rifampin.
Streptomycin.
Sulfa drugs.
Theophylline.
Tyrosine.
Other factors that may affect test results:
Exposure to direct sunlight or ultraviolet light may decrease bilirubin levels.
Failure to fast overnight.
*See Glossary.
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From Complete Guide to Medical Tests by H. Winter Griffith, M.D. Copyright by Fisher Books. Electronic rights by Medical Data Exchange.
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