Which laboratory finding should prompt the nurse to follow-up with a specific client?

A BNP (B-type natriuretic peptide) assay increasing to 1000 pg/mL is a critical laboratory finding that should prompt immediate follow-up. BNP is a hormone produced by the heart in response to increased intracardiac pressure and is an important marker in diagnosing and managing heart failure. Elevated levels indicate that the heart is under stress, and as the value rises, it typically correlates with worsening heart failure or cardiac distress. A level of 1000 pg/mL signifies significant concern and often requires further evaluation, possible intervention, or changes in management to prevent complications.

In contrast, normal white blood cell counts, potassium levels within normal limits, and fasting glucose levels under 100 mg/dL would generally not necessitate immediate follow-up, as they fall within expected ranges for healthy functioning. The other options are indicative of stable or normal physiological conditions, while the elevated BNP level represents a potentially urgent cardiac situation that demands attention.