The nurse reviews a client's laboratory results for a client admitted with gastrointestinal (GI) bleeding who has no visible hemorrhoids on inspection of the anal area. Which laboratory test indicates that the client's bleeding is not yet resolved?

Choice A rationale A decrease in Hemoglobin A1C from 10% to 8% indicates improved glycemic control over the past 2-3 months, as A1C reflects average blood glucose levels. This lab value is not directly indicative of acute or ongoing gastrointestinal bleeding resolution. Normal HbA1C is typically below 5.7%. Choice B rationale An increase in Prothrombin Time (PT) from 12 seconds (normal range 11-13.5 seconds) to 18 seconds indicates impaired clotting, which could be related to severe liver dysfunction or anticoagulant therapy, but it does not directly confirm ongoing GI bleeding. While bleeding may worsen with prolonged PT, it doesn't indicate active bleeding as the primary finding. Choice C rationale A change in Guaiac test from positive to negative indicates that occult blood is no longer detected in the stool, suggesting resolution of gastrointestinal bleeding. The guaiac test detects the peroxidase activity of hemoglobin; a negative result implies cessation of blood loss into the GI tract. Choice D rationale A decrease in Hematocrit (Hct) from 36% (normal range for adult males typically 40-54%) to 32% suggests ongoing blood loss or hemodilution. Hematocrit represents the percentage of red blood cells in blood volume. A continued drop indicates unresolved bleeding, as red blood cells are being lost from the circulatory system.