CLINICAL CHEMISTRY SECTION Flashcards
• Most automated area of the laboratory
- Doesn’t mean that medical technologists are
not needed [assisting and checking specimens]
- It is our duty to check the values and if it is
correct
CLINICAL CHEMISTRY SECTION
• Instruments are computerized and designed to
perform single and multiple tests from small
amounts of specimen
CLINICAL CHEMISTRY SECTION
AREAS IN CLINICAL CHEMISTRY
[routine chemistry tests: glucose, protein, etc]
General or automated chemistry
AREAS IN CLINICAL CHEMISTRY
[specialized procedure (not really
an area) for chemistry analysis; specimen is placed
on a gel-like medium and when the electric current
hits that, there will be a separation on different
components in that specimen]
Electrophoresis
AREAS IN CLINICAL CHEMISTRY
[area that monitors drugs of abuse]
Toxicology
AREAS IN CLINICAL CHEMISTRY
[immune assays and immunologic reactions]
Immunochemistry
• Tests are performed primarily on _________collected in
gel barrier tubes, but the ______may also be collected in tubes with red, green, gray, or royal
blue stoppers.
serum
(t or f) • Also performed on plasma, urine, and other body fluids
• Serum and plasma are obtained by centrifugation,
which should be performed within 1 to 2 hours of
collection
• Because many tests are performed on instruments
that take photometric readings, differences in the
appearance or color of a specimen may adversely
affect the test results
true
– appear red because of
the release of hemoglobin from rbcs [rejected]
Hemolyzed specimens
appear yellow because of
the presence of excess bilirubin [significant;
microscopic]
Icteric specimens
are cloudy [gelatin- like] because of increased lipids
[artificially made when the patient ate fatty meal before blood collection; if not, it is an indicator of something else]
Lipemic
specimens
•( t or f)
Fasting samples drawn from patients who have not
eaten for 8 to 12 [corrected: 10-12 hrs for testing
lipids and glucose] hours are preferred.
true
(t or f)
• Fasting samples drawn from patients who have not
eaten for 8 to 12 [corrected: 10-12 hrs for testing
lipids and glucose] hours are preferred.
• Serum separator tubes contain an inert gel that
prevents contamination of the specimen by RBCs or
their metabolites.
true
(t or f)
• Samples must be allowed to clot fully before
centrifugation to ensure complete separation of the
cells and serum. (wait at least 5 minutes)
• Many chemistry tests require special collection and
handling procedures, such as chilling and protection
from light (bilirubin)
- Cover with aluminum foil or carbon paper
true
• tests that are ordered by the health-care provider
to diagnose and monitor a patient’s condition.
• usually collected early in the morning but can be
collected throughout the day during scheduled
“sweeps” (collection times) on the floors or from
outpatients
ROUTINE SAMPLES
• “as soon as possible.”
• The response time for the collection of this test
sample is determined by each hospital or clinic and
may vary by laboratory tests.
ASAP SAMPLES
• means the sample is to be collected, analyzed,
and results reported immediately.
• highest priority and are usually ordered from the
emergency department or for a critically ill patient
whose treatment will be determined by the
laboratory result.
• The sample must be delivered to the laboratory
promptly and the laboratory personnel notified.
STAT SAMPLES
• The patient must only have refrained from eating
and drinking (except water) for 12 hours
• Drinking water is encouraged to avoid dehydration
in the patient, which can affect laboratory results.
• Test results most critically affected in a nonfasting
patient are those for glucose, cholesterol,
triglycerides, or lipid profiles.
• Prolonged fasting increases bilirubin and
triglyceride values and markedly decreases glucose
levels.
• When a fasting sample is requested, it is the
responsibility of the phlebotomist to determine
whether the patient has been fasting for the
required length of time.
• If the patient has not, this must be reported to a
supervisor or the nurse and noted on the
requisition form if the decision is made to collect
the sample nonfasting.
FASTING SAMPLES
• Hormones [specific time; follow instructions]
• Requisitions are frequently received requesting that
blood be drawn at a specific time.
• Phlebotomists should arrange their schedules to be
available at the specified time and should record
the actual time of collection on the requisition and
sample tube.
TIMED SAMPLES
• For the diagnosis of diabetes mellitus and
gestational diabetes [increase in blood sugar during
pregnancy: the mother is not hyperglycemic prior
pregnancy] [good indicator that the child has a
higher tendency to have diabetes]
• Included the 2-hour postprandial (pp) glucose test
and the classic glucose tolerance test (gtt).
GLUCOSE TOLERANCE TESTS
• Before the test, patients should be instructed to eat
a balanced diet that includes 150 g per day of
carbohydrates for 3 days and to fast for 12 hours
but not more than 16 hours.
• Certain medications can interfere with the test
results:
- Alcohol
- Anticonvulsants
- Aspirin
- Birth control pills
- Blood pressure medications
- Corticosteroids
- Diuretics
- Estrogen-replacement pills
GTT PREPARATION
• For glucose tolerance tests, the fasting patient
should be instructed to abstain from food and
drinks including coffee and unsweetened tea,
except water, for 12 hours but not more than 16
hours before and during the test.
• Smoking, chewing tobacco, alcohol, sugarless gum,
and vigorous exercise should be avoided before and
during the test because they stimulate digestion
and may cause inaccurate test results.
• Note on the requisition form if the patient is
chewing gum [stimulating saliva]
GTT PREPARATION
• Recommended method for the diagnosis of
diabetes mellitus.
• Requires the collection of a fasting glucose sample
[created by reagent suppliers], having the patient
drink a 75-g glucose solution within 5 minutes and
return for an additional glucose test in 2 hours.
• Diabetes mellitus= ≥200 mg/dl
- Kukuhanan dugo
- Papainumin ng glucose sample
- Kukuhanan ulit ng dugo
2-HOUR ORAL GLUCOSE TOLERANCE TEST
METHOD FOR GESTATIONAL
DIABETES
ONE-STEP METHOD and TWO-STEP METHOD
• Utilizes the same procedure as the diagnostic OGTT
used to diagnose diabetes mellitus [glucose drink
given only once]
• Norma value: ≤ 140 mg/dl
ONE-STEP METHOD
• Requires the patient to receive two tests.
• First a 50-g glucose challenge load is administered
to the fasting patient and blood collected and
tested at 1-hour postingestion.
• The second test is administered on a different day
and consists of either a 75-g OGTT or a 100-g 3-hour
OGTT based on institutional protocol and health-
care provider preferences.
• Normal Values:
- 2-hour 75-g test: 155mg/dL
- 3-hour 100-g test: 140 mg’dL
TWO-STEP METHOD
• Evaluates a patient’s ability to digest lactose, a milk
sugar.
• The enzyme mucosal lactase converts lactose into
glucose and galactose.
• Patients without this enzyme are unable to break
down lactose from milk and milk products, which
may result in gastrointestinal discomfort and
diarrhea.
LACTOSE TOLERANCE TEST
• Avoiding milk can reduce the symptoms.
• The patient is asked to drink a standardized amount
of lactose solution based on body weight in place of
the glucose.
• A blood collection schedule is similar to a 2-hour
GTT.
• Glucose levels will raise no more than 20 mg/dL
from the fasting sample result if the patient is
lactose intolerant.
LACTOSE TOLERANCE TEST