AMCA EXAM REVIEW PART 2 QUESTIONS
WITH CORRECT ANSWERS 2025
4.03 Identify the circumstances that can interfere in clinical analysis of blood constituents.
CORRECT ANSWER>>-
It is important to always work accurately and efficiently. With respect to specimen collection, t
he phlebotomy technician should take proper measures to prevent interference in the clinical a
nalysis of blood constituents. The presence of certain substances in the blood specimen can alt
er test results, depending on the types of tests being performed. To prevent interference, the
phlebotomy technician should be mindful of the following variables:
• Type of antiseptic -
The type of antiseptic used in specimen collection is determined by the tests being ordered.
➢ Isopropyl alcohol- The most common antiseptic used for cleaning a puncture site.
➢ Iodine -
When drawing samples for blood cultures, iodine is used to prevent contamination of the sam
ple by skin flora. Likewise, povidone-
iodine is used as an alternative to alcohol when prepping a puncture site for blood-
alcohol testing. Iodine is never used for dermal punctures because it will contaminate the sam
ple and interfere with results of certain tests, such as bilirubin, uric acid, and phosphorous test
s.
• Site selection -
The site from which a specimen is collected may cause interference as well. The following site
s should be avoided when performing venipunctures:
Part 2 of 4.03 CORRECT ANSWER>>-Hematomas -
Test results may be altered cause blood drawn from a hematoma not as fresh as venous blood
.
➢ The side of the body that has undergone mastectomy -
lymph stasis here can affect test results
➢ IV sites -
when possible, avoid drawing blood from an arm that has an IV in place. If no alternate site is
available, be sure to perform specimen collection from a site that is distal to (or below) the IV.
The 5 mL of blood should be discarded to prevent interference by the IV medications and fluid
s.
, • Specimen Collection -
Collecting specimens in the correct tubes and following the proper order of draw will help to
prevent contamination or interference. It is also important to ensure correct sample volume an
d to invert tubes properly.
• Tourniquet application -
Tying a tourniquet too tightly can result in hemoconcentration, or an increase in the proportio
n of cells to plasma. This can affect many results, including plasma proteins, enzymes, RBC cou
nts, iron, and potassium levels, among others. To prevent is, release the tourniquet as soon as
blood begins to flow in the first tube, and never leave it in place for longer than 1 minute.
4.04 Select proper antiseptic agents for the test. CORRECT ANSWER>>-
Before routine venipuncture selection, the patient's skin is cleaned with antiseptic to prevent c
ontamination by normal skin flora. Most commonly, 70% isopropyl alcohol is used. The antisep
tic should remain on the skin for 30-
60 seconds and allowed to dry before proceeding with the venipuncture. Do not fan, blow on,
or touch the site, as this may introduce more bacteria.
In certain situations, such as blood cultures or arterial punctures, Povidine-
iodine may be used. It is important not to use iodine for all venipuncture procedures, as it can
interfere with some chemistry test results. For patients older than 2 months of age with iodine
sensitivity, Chlorhexidine gluconate or benzalkonium chloride (Zephiran Chloride).
4.05 Select proper venipuncture equipment for the test and the size and the condition of veins
. CORRECT ANSWER>>-The following supplies are needed to perform venipuncture:
• Phlebotomy tray containing vacutainers, holders, needles, and syringes. *
• Tourniquet.
• Specimen labels.
• Disposable gloves.
• Sharp's container.
• 70% isopropyl alcohol.
• Gauze pads.
• Bandages.
WITH CORRECT ANSWERS 2025
4.03 Identify the circumstances that can interfere in clinical analysis of blood constituents.
CORRECT ANSWER>>-
It is important to always work accurately and efficiently. With respect to specimen collection, t
he phlebotomy technician should take proper measures to prevent interference in the clinical a
nalysis of blood constituents. The presence of certain substances in the blood specimen can alt
er test results, depending on the types of tests being performed. To prevent interference, the
phlebotomy technician should be mindful of the following variables:
• Type of antiseptic -
The type of antiseptic used in specimen collection is determined by the tests being ordered.
➢ Isopropyl alcohol- The most common antiseptic used for cleaning a puncture site.
➢ Iodine -
When drawing samples for blood cultures, iodine is used to prevent contamination of the sam
ple by skin flora. Likewise, povidone-
iodine is used as an alternative to alcohol when prepping a puncture site for blood-
alcohol testing. Iodine is never used for dermal punctures because it will contaminate the sam
ple and interfere with results of certain tests, such as bilirubin, uric acid, and phosphorous test
s.
• Site selection -
The site from which a specimen is collected may cause interference as well. The following site
s should be avoided when performing venipunctures:
Part 2 of 4.03 CORRECT ANSWER>>-Hematomas -
Test results may be altered cause blood drawn from a hematoma not as fresh as venous blood
.
➢ The side of the body that has undergone mastectomy -
lymph stasis here can affect test results
➢ IV sites -
when possible, avoid drawing blood from an arm that has an IV in place. If no alternate site is
available, be sure to perform specimen collection from a site that is distal to (or below) the IV.
The 5 mL of blood should be discarded to prevent interference by the IV medications and fluid
s.
, • Specimen Collection -
Collecting specimens in the correct tubes and following the proper order of draw will help to
prevent contamination or interference. It is also important to ensure correct sample volume an
d to invert tubes properly.
• Tourniquet application -
Tying a tourniquet too tightly can result in hemoconcentration, or an increase in the proportio
n of cells to plasma. This can affect many results, including plasma proteins, enzymes, RBC cou
nts, iron, and potassium levels, among others. To prevent is, release the tourniquet as soon as
blood begins to flow in the first tube, and never leave it in place for longer than 1 minute.
4.04 Select proper antiseptic agents for the test. CORRECT ANSWER>>-
Before routine venipuncture selection, the patient's skin is cleaned with antiseptic to prevent c
ontamination by normal skin flora. Most commonly, 70% isopropyl alcohol is used. The antisep
tic should remain on the skin for 30-
60 seconds and allowed to dry before proceeding with the venipuncture. Do not fan, blow on,
or touch the site, as this may introduce more bacteria.
In certain situations, such as blood cultures or arterial punctures, Povidine-
iodine may be used. It is important not to use iodine for all venipuncture procedures, as it can
interfere with some chemistry test results. For patients older than 2 months of age with iodine
sensitivity, Chlorhexidine gluconate or benzalkonium chloride (Zephiran Chloride).
4.05 Select proper venipuncture equipment for the test and the size and the condition of veins
. CORRECT ANSWER>>-The following supplies are needed to perform venipuncture:
• Phlebotomy tray containing vacutainers, holders, needles, and syringes. *
• Tourniquet.
• Specimen labels.
• Disposable gloves.
• Sharp's container.
• 70% isopropyl alcohol.
• Gauze pads.
• Bandages.
