Fecal leukocyte screening would be indicated in a patient with suspected:

• A. bacterial dysentery
• B. viral gastroenteritis
• C. parasitic infestation by Giardia lamblia
• D. lactose intolerance

Answer: (A)

Verified step by step guidance

1. Understand the clinical context: Fecal leukocyte screening is a diagnostic test used to detect the presence of white blood cells (leukocytes) in stool, which indicates inflammation in the intestinal mucosa.
2. Recall that bacterial dysentery, caused by invasive bacteria such as Shigella or certain strains of E. coli, typically leads to mucosal invasion and inflammation, resulting in fecal leukocytes.
3. Recognize that viral gastroenteritis usually does not cause mucosal invasion or significant inflammation, so fecal leukocytes are generally absent.
4. Note that parasitic infections like Giardia lamblia primarily cause malabsorption and do not typically induce a strong inflammatory response with leukocytes in stool.
5. Understand that lactose intolerance is a non-inflammatory condition caused by enzyme deficiency, so fecal leukocytes would not be expected.