Free NCMA Phlebotomy Procedures and Order of Draw Questions and Answers 1 — Questions and Answers
Question 1: A medical assistant is drawing blood for a CBC, a PT/INR, and a basic metabolic panel (BMP). What is the correct order of draw for these tests?
- Lavender, Light Blue, Red
- Light Blue, Red, Lavender (Correct answer)
- Red, Lavender, Light Blue
- Light Blue, Lavender, Red
Correct answer: Light Blue, Red, Lavender
The correct order of draw is based on the additives in the tubes to prevent cross-contamination. The light blue top (sodium citrate) for coagulation studies like PT/INR is drawn first after blood cultures. This is followed by the serum tube (red or gold top) for the BMP, and finally the lavender top (EDTA) for the CBC.
Question 2: Which additive is found in a lavender-topped evacuated tube?
- Sodium Citrate
- Heparin
- EDTA (Correct answer)
- Sodium Fluoride
Correct answer: EDTA
Lavender-topped tubes contain the anticoagulant Ethylenediaminetetraacetic acid (EDTA). EDTA works by binding calcium, which is essential for the clotting cascade, thus preventing the blood from clotting. These tubes are primarily used for hematology tests like a complete blood count (CBC).
Question 3: During a venipuncture, the area around the puncture site begins to swell and fill with blood. This is known as a:
- Hemoconcentration
- Phlebitis
- Petechiae
- Hematoma (Correct answer)
Correct answer: Hematoma
A hematoma is a collection of blood outside of a blood vessel, which occurs when the needle has gone through the vein or is only partially in the vein, causing blood to leak into the surrounding tissue. If this occurs, the tourniquet should be released and the needle withdrawn immediately, with pressure applied to the site.
Question 4: Which of the following sites should a medical assistant avoid for venipuncture?
- The dorsal side of the hand
- An arm on the same side as a mastectomy (Correct answer)
- The antecubital fossa of the non-dominant arm
- A site with a visible, palpable vein
Correct answer: An arm on the same side as a mastectomy
A medical assistant should avoid drawing blood from an arm on the same side as a previous mastectomy. The removal of lymph nodes during a mastectomy can impair lymphatic drainage, increasing the risk of infection and lymphedema if a venipuncture is performed on that arm. The other options are generally acceptable sites.
Question 5: What is the recommended angle of needle insertion for a routine venipuncture in the antecubital fossa?
- 5 to 10 degrees
- 45 degrees
- 15 to 30 degrees (Correct answer)
- 90 degrees
Correct answer: 15 to 30 degrees
The standard angle for needle insertion during a routine venipuncture is between 15 and 30 degrees. This angle allows the needle to enter the skin and then the vein without going through the vein or being too shallow. A steeper angle risks puncturing the back wall of the vein, while a shallower angle may not enter the vein properly.
Question 6: Which collection tube must be filled to its indicated capacity to ensure the proper ratio of blood to anticoagulant?
- Light Blue Top (Correct answer)
- Lavender Top
- Red Top
- Green Top
Correct answer: Light Blue Top
The light blue top tube, containing sodium citrate, requires a precise 9:1 ratio of blood to anticoagulant for accurate coagulation testing (e.g., PT/INR). Underfilling or overfilling the tube will alter this ratio and lead to erroneous test results. Other tubes are less sensitive to the fill volume, although a proper fill is always recommended.
Free NCMA Phlebotomy Procedures and Order of Draw Questions and Answers 1
A medical assistant is drawing blood for a CBC, a PT/INR, and a basic metabolic panel (BMP).
What is the correct order of draw for these tests?