1. A patient with a history of diabetes and hypertension is scheduled for a blood draw.

The nurse notices that the patient has a bruise on the antecubital area of the right

arm. What should the nurse do?

a) Use the left arm for the blood draw

b) Use the right arm and avoid the bruised area

c) Apply pressure on the bruise before the blood draw

d) Cancel the blood draw and notify the physician

*Answer: a) Use the left arm for the blood draw*

Rationale: Bruises indicate damaged blood vessels and tissues, which can affect the

quality and quantity of the blood sample. Using the left arm can avoid further injury

and ensure accurate results.

2. A patient with a suspected infection is ordered to have a complete blood count

(CBC) and a blood culture. The nurse has two sets of blood culture bottles, one for

aerobic and one for anaerobic bacteria. In what order should the nurse collect the

blood samples?

a) Blood culture (aerobic), blood culture (anaerobic), CBC

b) Blood culture (anaerobic), blood culture (aerobic), CBC

c) CBC, blood culture (aerobic), blood culture (anaerobic)

d) CBC, blood culture (anaerobic), blood culture (aerobic)

*Answer: b) Blood culture (anaerobic), blood culture (aerobic), CBC*

Rationale: Blood cultures are collected first to avoid contamination from

anticoagulants or additives in other tubes. Anaerobic bottles are filled first because

they are more sensitive to oxygen exposure. CBC tubes are filled last because they

contain anticoagulants that can interfere with bacterial growth.

3. A patient with a history of anemia is ordered to have a serum iron test. The nurse

knows that this test requires fasting for 12 hours before the blood draw. The patient

reports that he had a cup of black coffee and a glass of water this morning. What

should the nurse do?

a) Proceed with the blood draw as planned

b) Delay the blood draw for another 12 hours

c) Inform the laboratory about the patient's intake

d) Ask the patient to drink more water before the blood draw

*Answer: c) Inform the laboratory about the patient's intake*

Rationale: Black coffee and water are not considered as food, but they can still affect

the serum iron levels. The laboratory should be informed about the patient's intake so

that they can adjust the results accordingly or repeat the test if necessary.

4. A patient with a history of liver disease is ordered to have a prothrombin time (PT)

and an international normalized ratio (INR) test. The nurse knows that these tests

measure the clotting ability of the blood and are affected by warfarin, a medication

that the patient is taking. How should the nurse prepare the patient for the blood

draw?

a) Ask the patient to stop taking warfarin for 24 hours before the blood draw

b) Ask the patient to take warfarin as usual and note the dose and time of

administration

c) Ask the patient to take warfarin after the blood draw and note the dose and time of

administration

d) Ask the patient to take half of his usual dose of warfarin before the blood draw and

note it

*Answer: b) Ask the patient to take warfarin as usual and note the dose and time of

administration*

Rationale: Warfarin is a medication that affects the clotting ability of the blood and is