Question 1

A coagulation screen is ordered on a patient who is a difficult draw.A 5-mL blue top tube is drawn but fills only halfway.What would be the appropriate next step?

Accepted Answer

The ratio of anticoagulant to blood is critical for valid coagulation testing;thus the blue top tube must be filled.Combining two half-filled blue top tubes will result in twice as much anticoagulant.Sending the half-filled tube to the laboratory also results in too much anticoagulant for the volume of blood;thus both of these will invalidate coagulation tests,prolonging results.As soon as blood is drawn into a red top tube,it begins to clot and this will result in an activated specimen when it is added to the blue top tube,also invalidating results.

Question 2

At what temperature should blood samples be transported?

Accepted Answer

Blood samples for most tests can be safely transported at room temperature.However,specific tests require special transport temperatures,either on ice or at 37° C.These protocols must be followed to obtain valid results.

Question 3

What is the correct action to take if the patient refuses to have his or her blood drawn?

Accepted Answer

If a patient refuses to have his or her blood drawn,it is acceptable to politely try to persuade the patient to reconsider.However,if the patient still refuses,the phlebotomist should leave the room and inform the nurse that the patient refused the venipuncture.

Question 4

What is the most important step in the phlebotomy procedure?

Accepted Answer

Proper patient identification is critical and the most important step in performing phlebotomy.Failure to obtain and verify correct identification could result in serious,possibly even life-threatening,consequences for perhaps two patients.

Question 5

Which of the following would be an acceptable sample?

Accepted Answer

Fasting is not required to obtain a valid specimen for a CBC.Heparin is not the appropriate anticoagulant agent for a CBC.Coagulation tests should not be performed on a hemolyzed sample.The fluid in the intravenous line will contaminate a CBC drawn above an intravenous line,and all blood cell counts will be diluted and thus invalidly decreased.

Question 6

What is the best method to use for drying the alcohol from the arm before inserting the needle?

Accepted Answer

Alcohol used on the forearm should be allowed to air dry before performing venipuncture.Blowing on the arm will contaminant the site.Proceeding with the arm wet may result in a hemolyzed specimen;this may invalidate some test results and may also be painful for the patient.Wiping with gauze may also contaminate the site.

Question 7

What is the best method to use for increasing blood flow for capillary punctures?

Accepted Answer

The site for capillary puncture may be warmed using a warm,moist washcloth or a commercial warmer;it should be warmed to a temperature of no more than 42° C and for no longer than 2 to 5 minutes.Warming can increase the blood flow sevenfold.Exercise performed immediately before obtaining blood can invalidate a number of different tests,including white count and muscle enzymes.

Question 8

The preanalytic phase of clinical laboratory testing includes all of the following except

Accepted Answer

The preanalytic phase of testing begins with initiation of the test order and includes all the steps until the specimen is tested.Reporting of test results is part of the postanalytic phase of testing.

Question 9

When is the proper time to label a tube of blood?

Accepted Answer

Tubes of blood are labeled after the tube is drawn but before leaving the patient.Prelabeling tubes or labeling after an outpatient leaves or phlebotomist leaves the patient's room both carry the risk of mislabeling the tube with the wrong patient identification.

Question 10

Safety requirements for phlebotomy include:

Accepted Answer

Standard precautions require wearing gloves when performing phlebotomy;a face shield is not required unless splash is known to be a risk.Needles are never recapped (resheathed),and blood-contaminated gauze should be discarded in a biohazard bag.

Question 11

What information is not required on a blood tube label?

Accepted Answer

The patient name and identification number are both required on the blood tube label,as well as the initials of the phlebotomist for tracking should problems arise.The physician's name is not required on the blood tube label.

Question 12

Which of the following is the most important to prevent the spread of infection?

Accepted Answer

Washing hands using the proper technique best prevents the spread of infection.Other practices listed are also important to follow to contain contamination from (potentially)infectious specimens.

Question 13

What is the preferred site for phlebotomy on an adult?

Accepted Answer

The medial cubital vein located in the bend of the arm is the preferred site for phlebotomy on an adult.The basilic vein is also acceptable,as are veins on the top of the hand if no site can be found or used in the antecubital fossa (bend of the arm).The ring finger cannot be used for venipuncture.

Question 14

What is the recommended number of times for one phlebotomist to attempt to draw a patient?

Accepted Answer

A phlebotomist should ideally make only two attempts to obtain blood from a patient.If both of these venipuncture attempts are unsuccessful,another phlebotomist should be asked to continue.If two people have each failed twice,then the physician should be notified.

Question 15

What is the correct draw order when a complete blood count (CBC)and a PT are ordered?

Accepted Answer

When drawing blood for both a CBC (purple top)and PT (blue top),the blue top should be drawn before the purple top.Drawing them in the reverse runs the risk of contaminating the blue top tube with ethylenediaminetetraacetic acid (EDTA),which will invalidate the PT result.

Question 16

What test result is most affected by the absence of patient fasting?

Accepted Answer

Of the tests listed,only blood glucose is affected by the lack of fasting.None of the other procedures are significantly affected,although the white count may be slightly higher.

Question 17

What anticoagulant agent is used most often in the hematology laboratory?

Accepted Answer

EDTA is the anticoagulant agent of choice for routine hematology testing;it is found in the purple top tube.For routine coagulation testing,3.2% sodium citrate in the blue top is used,whereas heparin in the green top tube is used for some special tests,primarily in clinical chemistry.

Question 18

What is the correct procedure to follow if the site adjacent to the needle starts to swell profusely?

Accepted Answer

If the site adjacent to the venipuncture site starts to swell profusely,this indicates that blood is flowing into the surrounding tissue because the needle is not properly situated in the vein.The needle should be removed and pressure applied to the site to prevent further leakage of blood into tissue,causing an even larger hematoma.

Question 19

What is the preferred collection site on a patient being treated for blood clots who has an intravenous line in each forearm?

Accepted Answer

If no arm is available,blood should be drawn below the intravenous access site,with the tourniquet laced below the catheter site.It is also preferable to have the nurse stop the infusion for 2 minutes before the specimen is drawn.

Question 20

Hepatitis B virus can survive on a dried surface at room temperature for

Accepted Answer

The hepatitis B virus can survive on a dried surface at room temperature for up to 1 week.

Quiz 3: Blood Specimen Collection