Common Tests Flashcards
(50 cards)
What test are blood cultures tubes for
Blood cultures
What is the purpose of a Clear Top Tube?
Used as a discard tube to avoid contamination of other samples
A sample is drawn into this tube and then discarded to prevent thrombin and other cells from polluting subsequent samples.
What tube can replace a Clear Top Tube as a discard tube?
Red Top Tube
In some clinical settings, a Red Top Tube is used instead of a Clear Top Tube.
What additive is found in a Light Blue Top Tube?
Sodium Citrate
Sodium Citrate acts as an anticoagulant.
What does a Light Blue Top Tube yield?
Plasma
Plasma is obtained from samples drawn in this tube.
Which laboratory department is responsible for testing specimens from a Light Blue Top Tube?
Coagulation
In smaller laboratories, samples may be tested in the Hematology Department.
How does Sodium Citrate prevent coagulation?
By binding to calcium in the specimen
This helps preserve coagulation factors for testing.
What is the blood-to-additive ratio required for Sodium Citrate?
9 parts blood to 1 part additive
This specific ratio is crucial for accurate results.
What must be done to ensure the proper blood-to-additive ratio in the Light Blue Top Tube?
The tube must be filled completely
There is a line marked on the tube to indicate the proper amount.
How many times should the Light Blue Top Tube be inverted after collection?
3-4 times
This is necessary to mix the blood and additive properly.
What does current CLSI standards mandate before drawing a Light Blue Top Tube?
Draw a Clear Top Tube or Red Top Tube first
This prevents thromboplastin from contaminating the Light Blue Top Tube.
What is the effect of thromboplastin on coagulation study results?
It can affect the results negatively
Thromboplastin is released by tissue cells during venipuncture.
What is the function of the vacuum in the Light Blue Top Tube?
Clears the air line when using a winged infusion set
This is important to ensure accurate sample collection.
What does Prothrombin Time (PT) evaluate?
The extrinsic system of the coagulation cascade.
Therapeutic drug monitoring requires prothrombin time to be drawn when a patient is on a Coumadin regimen.
What does Partial Thromboplastin Time (PTT) evaluate?
The intrinsic system of the coagulation cascade.
Therapeutic drug monitoring requires partial thromboplastin time to be drawn when a patient is on a Heparin regimen.
What does Activated Partial Thromboplastin Time (aPTT) measure?
How long the patient’s blood takes to form a clot.
True or False: PTT and aPTT are used to test for the same functions.
True.
In aPTT, what is added to speed up the clotting time?
An activator.
What is the result of adding an activator in aPTT?
A narrower reference range.
What is the primary use of a Red Top Tube?
It is frequently used as a discard tube to prevent sample contamination.
It is sometimes used to clear the line to obtain a purer sample.
What is the additive in a Red Top Tube?
None - Glass
If the tube is plastic, a clotting agent may be added.
What does a Red Top Tube yield?
Serum
This tube is used for serum testing.