Frequently Asked Questions
Chapter 29: Diagnostic Testing

What is the purpose of preparing a client for diagnostic testing?

Preparation promotes client cooperation, enhances the quality of the testing and decreases the time required to perform the study in a safe, efficient, and cost-effective manner.

How does the nurse prepare a client for diagnostic testing?

The nurse (1) ensures that the client is wearing an identification band; (2) checks for allergies and monitors for adverse reactions; (3) monitors the client’s knowledge level and understanding concerning the test; (4) explains the reason for each test, how long a test will taken, and other information peculiar to a specific test; (5) monitors vital signs for baseline data; (6) monitors clients who are on NPO (nothing by mouth) restrictions; (7) administers cathartics or laxatives if part of the test protocol; (8) teaches clients relaxation techniques to use during diagnostic procedures, (9) establishes intravenous (IV) access if necessary; (10) monitors client’s response to testing; and (11) documents the client’s responses.

What is the care given by the nurse during a diagnostic test?

During a diagnostic test, the nurse explains what happens during the test, answers questions, explains what to expect after the test, and explains what to report after the test. The nurse also documents who performed the procedure, the reason for the procedure, the type of medications used during the procedure, the type of specimen obtained, vital signs, any symptoms, and who transported the client to another area.

What is the difference between sensitivity and specificity?

Sensitivity is the likelihood that a diseased client has a positive result. If a test has 100% sensitivity, all clients with the disease will have positive results and all clients without the disease will have negative results. Specificity is the likelihood that a healthy individual will have negative results. If a test has 100% specificity, all clients without a given disease will have negative results.

What is the care given to the client after a diagnostic test?

After a diagnostic test, the nurse (1) observes vital signs; (2) checks for bleeding and other complications; (3)maintains aseptic technique; (4) reports signs and symptoms to the practitioner; (5) implements orders related to postprocedure care; (6) enforces activity restrictions; (7) teaches the client or family precautions related to the procedure; and (8) documents assessment, intervention, teaching, and evaluative data.

What is the purpose of cleansing a venipuncture site with an alcohol swab?

The purpose of cleansing a venipuncture site with an alcohol swab is to cleanse the skin surface of bacteria that might cause infection at the site.

What are the three sources of venipuncture variability that should be considered by the nurse?

The three sources of venipuncture variability that should be considered by the nurse are (1) hemoconcentration (reduced volume of plasma water), caused by prolonged standing or a prolonged time of application of a tourniquet during venipuncture; (2) hemolysis (breakdown of red blood cells and the release of hemoglobulin, usually caused by using small-bore needles; and (3) using blood drawn from a site above an intravenous infusion, causing contamination with intravenous fluid.

Why are arterial blood gases not drawn within 20 minutes after a respiratory treatment?

Arterial blood gases are not drawn within 20 minutes after a respiratory treatment to ensure accurate determination of the client’s actual blood gases.