Which laboratory result requires immediate intervention from the nurse?

The laboratory result indicating a decrease of 50% in platelets in a heparin-treated patient is particularly concerning as it may suggest heparin-induced thrombocytopenia (HIT). HIT is a potentially life-threatening condition where the body's immune response leads to a significant drop in platelet counts, increasing the risk of thrombosis. Such a significant decline in platelets requires immediate nursing intervention to prevent further complications, such as thromboembolic events.

While the other options present concerning clinical situations, they do not warrant the same level of urgent intervention. A blood glucose level of 250 in a type 2 diabetic suggests that the patient is hyperglycemic but may not require immediate action unless symptomatic. An A1C level of 10.5 indicates chronic high blood sugar but is more indicative of poor long-term management rather than an acute crisis. Mild hypertension in a post-streptococcal glomerulonephritis patient should be monitored, but it typically does not require immediate intervention unless it is severe or accompanied by other troubling symptoms.

In contrast, a 50% decrease in platelets in a patient receiving heparin is alarming and requires prompt assessment and intervention to manage the risk of serious complications.