Module 5 Flashcards
Compounds added to biological specimens to prevent them from clotting or to preserve
the constituents of a specimen.
additives
Any substance that prevents blood from clotting
anticoagulant
A prenatal test to detect birth defects that is performed at an early stage of pregnancy
and involves retrieval and examination of tissue from the organ.
chorionic villi sampling
The sequential process by which the multiple coagulation factors of blood interact in the
coagulation cascade, resulting in formation of an insoluble fibrin clot.
coagulation or clotting
Variation that occurs in the amount of a substance during a 24-hour period.
diurnal variation
Disruption of the red cell membrane causing release of hemoglobin and other components of red blood cells.
hemolysis
Disruption of the red cell membrane causing release of hemoglobin and other components of red blood cells.
hemolysis
The individual drawing a specimen of blood.
phlebotomist
The puncture of a blood vessel to collect blood.
phlebotomy
Factors that affect specimens before tests are performed and that can lead to error if not controlled; they are classified as controllable or uncontrollable.
pre-analytical factors
A substance or preparation added to a specimen to prevent changes in the constituents
of a specimen.
preservatives
The non-cellular component of anticoagulated whole blood; plasma contains clotting factors.
plasma
The watery portion of blood that remains after coagulation has occurred and can be obtained after centrifugation
serum
Collection of capillary blood usually from a pediatric patient by making a thin cut in the
skin, usually at the heel of the foot.
skin puncture
Obstruction of the return of venous blood to the heart and distention of the veins; in phlebotomy, this is a temporary blockage caused by application of pressure, usually from
a tourniquet.
venous occlusion
usually the specimen of choice
venous blood
Aside from venipuncture, blood samples can be collected using a skin puncture technique that can be done on
heel stick
middle or fourth finger
earlobe
uses both the liquid portion of the blood called plasma and the cellular components
whole blood
cellular components of blood
RBC
WBC
platelets
type of whole blood that is oxygenated and have uniform composition throughout the body
arterial blood
arterial blood is used in measuring:
pH
arterial blood gas
why is syringe used in arterial blood collection instead of evacuated tubes
because of the pressure in the arteries
primary arterial sites
radial
brachial
femoral
primary arterial sites
radial
brachial
femoral
hazards of arterial collection
arterial pressure
difficulty in stopping bleeding
hematoma
disadvantages of arterial blood
technically difficult
more painful
not used for routine tests
advantages of arterial blood
blood gas analysis
best for respiratory function
high exygen content
consistency
samples are deoxygenated and have variable composition
venous blood
direct puncture to collect venous blood is often located in the
antecubital area
venous blood differs from arterial blood in the concentration of
chloride, glucose, pH, CO2, lactic acid, ammonia
advantages of venous blood
good indicator
easier to obtain
used most frequently
disavantages of venous blood
minor and serious complications
lack of accessible veins
fear of needles
content of capillary blood
arterial blood
venous blood
tissue fluid
Point-of-care testing is often performed using this
capillary blood
capillary blood has higher
glucose
capillary blood has lower
Ca, K, total protein concentrations
advantages of capillary blood
small amounte needed
simple and painless
can change sites
disadvantages of capillary blood
not all tests
can rupture blood cells
calcofied nodules may develop in site
percentage of blood that is plasma
55%
percentage of plasma that is water
92%
other components of plasma
7% proteins
1% mineral salts, sugar, fat, hormone, vitamins
serum is absent of
Factor I, V, VIII, XIII
1 5 8 13
how long does blood clot with thrombin
5 minutes
how long does blood clot with clot activator
30 mins
