Question 1

Before a routine venipuncture or capillary puncture,the site typically is cleaned with

Accepted Answer

Isopropyl alcohol is the most widely used and recommended antiseptic solution for routine venipuncture and capillary puncture procedures. It is effective in killing most microorganisms on the skin's surface and is quick-drying, ensuring minimal patient discomfort and less interference in the collection process. Ethyl alcohol and povidone-iodine are also used for skin sterilization, but they have certain limitations, such as not being as effective against certain viruses or having a longer drying time. Soap and water are not recommended for site cleaning as they do not provide adequate disinfection.

Question 2

The slant at the open end of a needle used for venipuncture is called the

Accepted Answer

The slant at the open end of a needle used for venipuncture is called the bevel. The lumen refers to the hollow center of the needle where blood flows, the shaft refers to the length of the needle, and the bore refers to the diameter of the needle.

Question 3

You are required to collect a venous sample for a typical hematology test,the complete blood count.You collect

Accepted Answer

A lavender-topped tube is the best choice for collecting a venous sample for a complete blood count. This tube contains the anticoagulant ethylenediaminetetraacetic acid (EDTA), which prevents the blood from clotting and preserves the morphology of the blood cells.

Question 4

A tourniquet should remain tied on a patient's arm no longer than

Accepted Answer

Leaving a tourniquet on for longer than 1 minute greatly increases the possibility of hemoconcentration and altered test results.

Question 5

A syringe is preferred over a Vacutainer collection device when

Accepted Answer

Syringes are used when there is concern that the strong vacuum in a stoppered tube may collapse the vein.

Question 6

A tourniquet is used during the phlebotomy procedure to

Accepted Answer

The tourniquet is used to prevent venous flow out of the site, which causes the vein to bulge and makes it easier to locate and access for the phlebotomy procedure. The collapse of the artery is not the intended use of the tourniquet.

Question 7

The needle size most commonly used in infants and the elderly is _____ gauge.

Accepted Answer

The smallest-gauge needles (23 gauge) are used to collect blood from small or fragile veins, such as those of elderly or very young patients.

Question 8

In a routine venipuncture,the angle at which the needle enters the arm should be _____ degrees.

Accepted Answer

The needle should enter the arm at a 15-degree angle, parallel to the vein, so as to puncture the vein without passing through it.

Question 9

No anticoagulants are found in which of the following tubes?

Accepted Answer

Red topped tubes do not contain any anticoagulants. They are used for collecting blood samples for serum testing, where clotting is necessary to separate the serum from the clotted blood cells. Lavender topped tubes contain EDTA as an anticoagulant, green topped tubes contain heparin as an anticoagulant, and yellow topped tubes contain ACD (acid citrate dextrose) as an anticoagulant.

Question 10

Which type of tube should be used to collect blood specimens during a glucose tolerance test?

Accepted Answer

A glucose tolerance test requires the collection of multiple blood samples over a period of time, typically before drinking a glucose solution and at defined intervals afterwards. The gray topped tube contains sodium fluoride, which is a preservative that can help stabilize glucose levels in the blood sample. This tube may also contain potassium oxalate, which helps prevent clotting of the blood during testing.

Question 11

During a routine venipuncture,when should the phlebotomist request that the patient "make a fist"?

Accepted Answer

The phlebotomist should request the patient to make a fist after applying the tourniquet and before inserting the needle. This helps to increase venous pressure and makes the vein more prominent, making it easier to locate and insert the needle.

Question 12

The needle size most commonly used by the blood bank for donations is _____ gauge.

Accepted Answer

Blood bank donation requires a larger-gauge needle; using a 16-gauge needle to collect blood reduces the chance of hemolysis.

Question 13

Plasma could be retrieved from a

Accepted Answer

Plasma can be retrieved from a PST green-gray tube and a SST red-gray tube, but not from a lavender tube. Therefore, choices B and C are correct and A is incorrect. The correct answer is D, as it includes both correct choices.

Question 14

The laboratory requisition indicates that you are to collect a venous blood specimen for hematology testing,serum chemistry testing,and coagulation studies.What is the proper order of collection for these tubes?

Accepted Answer

The proper order of collection for a venous blood specimen for hematology testing, serum chemistry testing, and coagulation studies is light blue (for coagulation studies), red (for serum chemistry testing), and lavender (for hematology testing). This is because the coagulation tube should be collected first in order to prevent cross-contamination of the other tubes with anticoagulants, which can affect the test results.

Question 15

Without a clot activator,whole blood typically clots in _________ minutes.

Accepted Answer

Clot activators promote clotting of blood. Without a clot activator, blood clots in 30 to 60 minutes, after which it must be centrifuged.

Question 16

The needle size most commonly used for adult venipuncture is _____ gauge.

Accepted Answer

The needle size most commonly used for adult venipuncture is 21 gauge. This size is appropriate for most veins and is less painful for the patient.

Question 17

The ____________ is the part of the venipuncture needle that fits into the syringe or Vacutainer adapter.

Accepted Answer

The hub is the part of the venipuncture needle that fits into the syringe or Vacutainer adapter. The shaft is the long, thin portion of the needle that is inserted into the vein. The bevel is the angled tip of the needle that pierces the skin and vein. The retractable sheath is a safety feature that covers the needle after use to prevent accidental needlestick injuries.

Question 18

Leaving a tourniquet tied on a patient's arm for longer than the recommended time results in

Accepted Answer

Leaving a tourniquet tied on a patient's arm for longer than the recommended time can lead to hemoconcentration, which is an increase in the concentration of blood cells and other components due to decreased blood flow. This can result in inaccurate laboratory test results and potential harm to the patient. Syncope refers to fainting, hematoma formation is a localized collection of blood outside the blood vessels, and bifurcation refers to the splitting of a blood vessel into two branches. None of these are direct consequences of leaving a tourniquet tied too long.

Question 19

_______________________________ is an anticoagulant that prevents platelets from clumping and preserves the appearance of blood cells for microscopic preparation.

Accepted Answer

Ethylenediamine tetraacetic acid (EDTA) is an anticoagulant that prevents platelets from clumping and preserves the appearance of blood cells for microscopic preparation. Thrombin is not an anticoagulant and sodium heparin and sodium polyanetholsulfonate are anticoagulants but do not preserve the appearance of blood cells for microscopic preparation.

Question 20

Which of the following Vacutainer tubes is routinely used for hematology testing?

Accepted Answer

Lavender-topped Vacutainer tubes contain ethylenediaminetetraacetic acid (EDTA), which is used as an anticoagulant and are commonly used for hematology testing, including complete blood counts and blood smears. Red, green, and light blue topped tubes are used for other types of testing, such as chemistry, blood bank, and coagulation testing.

Quiz 29: Assisting in Blood Collection