The nurse teaches a pregnant woman about the presumptive, probable, and positive signs of pregnancy.
The woman demonstrates understanding of the nurse's instructions if she states that a positive sign of pregnancy is:.

Choice A rationale:
Bronchoscopy is not the essential test for diagnosing cystic fibrosis. Bronchoscopy is a procedure that allows the healthcare provider to visualize the airways and lungs but is not the primary test for cystic fibrosis diagnosis. Cystic fibrosis is primarily diagnosed through genetic testing and sweat chloride testing.
Choice B rationale:
Serum calcium levels are not specific to cystic fibrosis diagnosis. Serum calcium levels are typically used to assess calcium balance in the body and are not directly related to cystic fibrosis diagnosis.
Choice C rationale:
Urine creatinine levels are not specific to cystic fibrosis diagnosis. Urine creatinine levels are often used to assess kidney function and muscle breakdown but are not diagnostic for cystic fibrosis.
Choice D rationale:
Sweat chloride test is essential in establishing the diagnosis of cystic fibrosis. Cystic fibrosis is characterized by the abnormal transport of chloride across cell membranes, leading to salty sweat. The sweat chloride test measures the amount of chloride in the sweat and is a key diagnostic test for cystic fibrosis. Values above a certain threshold (typically 60 mmol/L) are suggestive of cystic fibrosis.

Choice A rationale:

Ribbon-like stools are not characteristic of intussusception. Intussusception is a medical emergency where one portion of the intestine invaginates or telescopes into another. This condition can lead to intestinal obstruction and compromised blood flow, causing severe abdominal pain, vomiting, and bloody stools. The characteristic stool appearance associated with intussusception is "currant jelly" stools. These stools contain mucus, blood, and sloughed mucosal tissue, giving them a characteristic dark, sticky, and jelly-like appearance. This occurs due to the mixture of blood and mucus within the intestines.

Choice B rationale:

Hard stools positive for guaiac indicate the presence of occult blood in the stool, but this finding is not specific to intussusception. Occult blood in the stool can be a sign of gastrointestinal bleeding from various causes, such as ulcers, gastritis, or colorectal polyps. It is not a characteristic feature of intussusception.

Choice D rationale:

Loose, foul-smelling stools are nonspecific and can occur due to various gastrointestinal disorders, dietary issues, or infections. This description does not specifically indicate intussusception.