A nurse is reinforcing teaching with the partner of a client who has contact precautions in place for methicillin-resistant Staphylococcus aureus (MRSA).
Which of the following statements by the client's partner indicates an understanding of the teaching?

Palpable area of induration, greater than 10 mm (0.4 in) in diameter. This indicates a positive tuberculin skin test (TST) reaction for a person with no known risk factors for TB infection. A positive TST reaction means that the person has been infected with Mycobacterium tuberculosis, the bacterium that causes TB disease, and needs further testing to confirm the diagnosis and rule out active TB disease.

The other choices are not correct because:

- Choice A. Nonpalpable area of redness, less than 5 mm (0.2 in) in diameter. This indicates a negative TST reaction for any person, regardless of their risk factors for TB infection. A negative TST reaction means that the person has not been infected with Mycobacterium tuberculosis or has a very low level of immune response to the bacterium.

- Choice B. Area of ecchymosis, greater than 12 mm (0.5 in) in diameter. This indicates a bruise or bleeding under the skin, not a TST reaction. Ecchymosis is not caused by the injection of tuberculin purified protein derivative (PPD) into the skin, but by trauma or injury to the blood vessels.

- Choice C. Tenderness at the injection site. This indicates a mild local reaction to the injection of tuberculin PPD into the skin, not a TST reaction. Tenderness is not measured in millimeters of induration (firm swelling), which is the standard way of reading TST results.

knee-chest. During sigmoidoscopy, the client should lie on their left side with their right knee flexed slightly. The nurse should then position the client in the knee-chest (Sims) position, where the client leans forward with bent knees and support the chest and forearms on the table or a pillow. This allows better visualization and access to the rectal area for the sigmoidoscopy procedure.

An explanation for incorrect choices:

A. Orthopneic position is upright sitting with arms and elbows resting on a table or on a pillow, which helps clients who have difficulty breathing; it is not suitable for sigmoidoscopy.

B. Trendelenburg position

is supine with the head lower than the feet, which can cause blood flow to the head and increased intracranial pressure; it is not suitable for sigmoidoscopy.

C. Prone position is lying face down, which is not suitable for sigmoidoscopy.