**Core Concept**
SIRS (Systemic Inflammatory Response Syndrome) is a clinical condition characterized by a non-specific inflammatory response to an insult, which can be infectious or non-infectious. The diagnosis of SIRS is based on the presence of two or more of the following criteria: body temperature, heart rate, respiratory rate, and white blood cell count.

**Why the Correct Answer is Right**
The correct answer, **Option D:** >50% immature neutrophils, is incorrect because the diagnostic criteria for SIRS in children do not include the percentage of immature neutrophils. The correct criteria for SIRS in children include temperature, heart rate, respiratory rate, and white blood cell count. A persistent bradycardia over 0.5 hour in children 38.5°C or SD above normal for age is a correct criterion for SIRS in children.
**Option D:** >50% immature neutrophils is not a criterion for SIRS, making it the correct answer to the question.

**Clinical Pearl / High-Yield Fact**
It's essential to remember the diagnostic criteria for SIRS in children, which include temperature, heart rate, respiratory rate, and white blood cell count. A persistent bradycardia over 0.5 hour in children 50% immature neutrophils