NCCT PHLEBOTOMY LATEST EXAM QUESTIONS AND
ANSWERS
Which of the following specimens is most susceptible to cross contamination and
should always be drawn first?
blood culture
Rationale
Since blood cultures test for sepsis (infection in the blood stream), the skin should be
specially prepared to avoid contaminating the specimen during the collection process
with normal skin bacteria. The exact preparation protocol may vary slightly among
services, but most phlebotomy procedures will either use an iodine solution,
ChloraPrep, or equivalent chlorhexidine-based skin antisepsis solutions. When blood
cultures are ordered along with other laboratory testing, collect the blood cultures first.
The regular alcohol pre-draw prep is sufficient for the CBC, cholesterol, and hematocrit
(HCT can be ordered separately, but is included within a CBC).
Which of the following evacuated tubes should the medical assistant draw first?
light blue top
Rationale
CLSI lists the order of draw as follows: 1. Blood cultures 2. Coagulation tube (e.g. blue
closure) 3. Serum tube with or without clot activator, with or without gel (e.g. red
closure, gold shield,etc.) 4. Heparin tube with or without gel plasma separator (e.g.
green closure) 5. EDTA tube with or without gel separator (e.g. lavender closure, pearl
closure) 6. Glycolytic inhibitor (e.g. gray closure) Other tube additives affect coagulation
tests. Collecting the light blue top tube (for coagulation testing) in this scenario prevents
contamination of the specimen with tissue thromboplastin (which will adversely affect
the test).
The physician has ordered a prothrombin time (PT) and complete blood count
(CBC) for an adult patient with a diagnosis of thrombophlebitis. The medical
assistant should collect the evacuated tubes in which of the following orders?
,blue, lavender
Rationale
In the past, there was concern that the first blood collected into a tube or syringe was
contaminated with tissue thromboplastin resulting from the entry of the needle into the
skin. The presence of tissue thromboplastin in a blue top tube could alter the results of
the routine coagulation tests, protime (PT) and activated partial thromboplastin (aPTT).
Therefore, it was necessary to collect a small quantity of blood in another tube to assure
that no tissue thromboplastin would contaminate the blue top tube. Research now
indicates that the amount of tissue thromboplastin generated from a venipuncture today
is minimal and will not affect the results of PT and aPTT testing. However, studies have
not been performed for other coagulation tests so a discard tube should be filled with a
small volume of blood prior to collecting blood into a blue top tube. NOTE: The "no
discard tube needed" policy applies only when using a routine venipuncture with
needle/tube holder or needle/syringe. A lavender (EDTA) tube is the appropriate tube to
collect for a CBC test. CLSI (Clinical and Laboratory Standards Institute) lists the order
of draw as follows: 1. Blood culture tube 2. Coagulation tube (eg, blue closure) 3. Serum
tube with or without clot activator, with or without gel (eg, red closure) 4. Heparin tube
with or without gel plasma separator (eg, green closure) 5. EDTA tube with or without
gel separator.
Identify the CLSI recommended micro-collection order of draw for a BMP, CBC &
Bilirubin.
EDTA, Heparin, Serum Separator
Rationale
The recommended Order of Draw for capillary blood collection is different from blood
specimens drawn by venipuncture. CLSI recommends the following order of draw for
skin puncture: Blood gases, EDTA tubes, Other additive tubes, then Serum tubes.
Blood cultures are always drawn first because?
to avoid contamination of the cultures.
Rationale
, When sepsis is suspected, the physician orders blood cultures. Specimen collection for
blood cultures is more detailed than for routine venipuncture, thus adding collection
time. Blood cultures are always drawn first to avoid contamination from drawing
additional tubes. It is necessary to disinfect the draw site before collecting blood
cultures so they are not contaminated with normal skin flora. Contamination can result
in unreliable test results, which in turn can lead to incorrect diagnosis and treatment of
the patient. Blood culture bottles are sterile and the different colored tops indicate
different additives.
A phlebotomist is asked to collect a CBC, PT and Chem 7 on a patient that
requires a hand stick with a butterfly needle into evacuated tubes. The correct
order of draw for this collection would be
Two Light Blue Top Tubes, Green Top Tube, Lavender Top Tube
Rationale
The correct order of draw would be: two light blue top tubes (one waste and one for PT
which is a coagulation test), green top tube (for the Chem 7), and the lavender top tube
(for the CBC).
Which of the following actions should the medical assistant take to prevent
hemolysis of a blood specimen in an EDTA tube?
Gently invert the tube after collecting the specimen.
Rationale
Since an EDTA tube contains anticoagulant, it is important to immediately mix the blood
as soon as it is collected to ensure that it doesn't clot. The medical assistant should
gently invert the tube after collecting the specimen to maintain specimen integrity and
prevent rupture of RBC's in the sample. The smaller gauged needles would introduce a
higher likelihood of hemolysis, not prevent it. Refrigerated storage would not necessarily
prevent immediate hemolysis (but would slow down the breakdown of RBCs that would
cause hemolysis over time). The tube should be gently mixed immediately after
collection and can be processed and run as soon as needed (it does not need to stand
ANSWERS
Which of the following specimens is most susceptible to cross contamination and
should always be drawn first?
blood culture
Rationale
Since blood cultures test for sepsis (infection in the blood stream), the skin should be
specially prepared to avoid contaminating the specimen during the collection process
with normal skin bacteria. The exact preparation protocol may vary slightly among
services, but most phlebotomy procedures will either use an iodine solution,
ChloraPrep, or equivalent chlorhexidine-based skin antisepsis solutions. When blood
cultures are ordered along with other laboratory testing, collect the blood cultures first.
The regular alcohol pre-draw prep is sufficient for the CBC, cholesterol, and hematocrit
(HCT can be ordered separately, but is included within a CBC).
Which of the following evacuated tubes should the medical assistant draw first?
light blue top
Rationale
CLSI lists the order of draw as follows: 1. Blood cultures 2. Coagulation tube (e.g. blue
closure) 3. Serum tube with or without clot activator, with or without gel (e.g. red
closure, gold shield,etc.) 4. Heparin tube with or without gel plasma separator (e.g.
green closure) 5. EDTA tube with or without gel separator (e.g. lavender closure, pearl
closure) 6. Glycolytic inhibitor (e.g. gray closure) Other tube additives affect coagulation
tests. Collecting the light blue top tube (for coagulation testing) in this scenario prevents
contamination of the specimen with tissue thromboplastin (which will adversely affect
the test).
The physician has ordered a prothrombin time (PT) and complete blood count
(CBC) for an adult patient with a diagnosis of thrombophlebitis. The medical
assistant should collect the evacuated tubes in which of the following orders?
,blue, lavender
Rationale
In the past, there was concern that the first blood collected into a tube or syringe was
contaminated with tissue thromboplastin resulting from the entry of the needle into the
skin. The presence of tissue thromboplastin in a blue top tube could alter the results of
the routine coagulation tests, protime (PT) and activated partial thromboplastin (aPTT).
Therefore, it was necessary to collect a small quantity of blood in another tube to assure
that no tissue thromboplastin would contaminate the blue top tube. Research now
indicates that the amount of tissue thromboplastin generated from a venipuncture today
is minimal and will not affect the results of PT and aPTT testing. However, studies have
not been performed for other coagulation tests so a discard tube should be filled with a
small volume of blood prior to collecting blood into a blue top tube. NOTE: The "no
discard tube needed" policy applies only when using a routine venipuncture with
needle/tube holder or needle/syringe. A lavender (EDTA) tube is the appropriate tube to
collect for a CBC test. CLSI (Clinical and Laboratory Standards Institute) lists the order
of draw as follows: 1. Blood culture tube 2. Coagulation tube (eg, blue closure) 3. Serum
tube with or without clot activator, with or without gel (eg, red closure) 4. Heparin tube
with or without gel plasma separator (eg, green closure) 5. EDTA tube with or without
gel separator.
Identify the CLSI recommended micro-collection order of draw for a BMP, CBC &
Bilirubin.
EDTA, Heparin, Serum Separator
Rationale
The recommended Order of Draw for capillary blood collection is different from blood
specimens drawn by venipuncture. CLSI recommends the following order of draw for
skin puncture: Blood gases, EDTA tubes, Other additive tubes, then Serum tubes.
Blood cultures are always drawn first because?
to avoid contamination of the cultures.
Rationale
, When sepsis is suspected, the physician orders blood cultures. Specimen collection for
blood cultures is more detailed than for routine venipuncture, thus adding collection
time. Blood cultures are always drawn first to avoid contamination from drawing
additional tubes. It is necessary to disinfect the draw site before collecting blood
cultures so they are not contaminated with normal skin flora. Contamination can result
in unreliable test results, which in turn can lead to incorrect diagnosis and treatment of
the patient. Blood culture bottles are sterile and the different colored tops indicate
different additives.
A phlebotomist is asked to collect a CBC, PT and Chem 7 on a patient that
requires a hand stick with a butterfly needle into evacuated tubes. The correct
order of draw for this collection would be
Two Light Blue Top Tubes, Green Top Tube, Lavender Top Tube
Rationale
The correct order of draw would be: two light blue top tubes (one waste and one for PT
which is a coagulation test), green top tube (for the Chem 7), and the lavender top tube
(for the CBC).
Which of the following actions should the medical assistant take to prevent
hemolysis of a blood specimen in an EDTA tube?
Gently invert the tube after collecting the specimen.
Rationale
Since an EDTA tube contains anticoagulant, it is important to immediately mix the blood
as soon as it is collected to ensure that it doesn't clot. The medical assistant should
gently invert the tube after collecting the specimen to maintain specimen integrity and
prevent rupture of RBC's in the sample. The smaller gauged needles would introduce a
higher likelihood of hemolysis, not prevent it. Refrigerated storage would not necessarily
prevent immediate hemolysis (but would slow down the breakdown of RBCs that would
cause hemolysis over time). The tube should be gently mixed immediately after
collection and can be processed and run as soon as needed (it does not need to stand
