A sepsis patient admitted in ICU. Which laboratory value is abnormal?

Appeared in: NORCET 8 Prelims-2025

Explanation

Lactate is a product of anaerobic metabolism, which occurs when cells lack sufficient oxygen.
In sepsis, widespread inflammation can impair oxygen delivery to tissues, leading to a switch to anaerobic metabolism and lactate production.
A serum lactate level greater than 2 mmol/L is a key indicator of tissue hypoperfusion and is used in the diagnosis of septic shock.
A level of 5.5 mmol/L is critically elevated, signifying significant organ dysfunction and a high risk of mortality.

Option A: A White Blood Cell (WBC) count of 9,000 cells/mm3 falls within the typical normal range (5,000-10,000/mm3).
Option B: A Random Blood Sugar (RBS) of 110 mg/dL is a normal finding. The normal range for a non-diabetic person is typically 70-140 mg/dL.
Option C: A urine output of 1.5 mL per minute is equivalent to 90 mL per hour. This indicates adequate renal perfusion.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Interpretation of laboratory values in sepsis in acute care settings.
Monitoring serum lactate is a critical nursing responsibility in managing patients with sepsis. It provides a real-time indicator of tissue perfusion and the effectiveness of resuscitation efforts.
A rising lactate level is a red flag that requires immediate escalation to the medical team and may prompt interventions like increased fluid administration or initiation of vasopressors.
What if? If the patient's lactate level decreased from 5.5 mmol/L to 2.5 mmol/L after a fluid bolus, it would indicate a positive response to treatment, suggesting improved tissue perfusion. However, the level is still elevated, requiring continued monitoring and intervention.

How to Approach the Question

First, identify the core of the question: you need to find the ABNORMAL lab value for a patient with a specific condition (sepsis).
Next, evaluate each option against the standard normal ranges for that laboratory test.
Option A: WBC 9000. Is this normal? Yes, 4,500-11,000 is the general range.
Option B: RBS 110 mg/dL. Is this normal? Yes, random glucose is usually under 140 mg/dL.
Option C: Urine output 1.5 mL/min. Convert this to a more familiar unit: 1.5 mL/min * 60 min/hr = 90 mL/hr. Is this adequate? Yes, it's well above the minimum of 0.5 mL/kg/hr.
Option D: Lactate > 5.5 mmol/L. Is this normal? No, normal lactate is less than 2 mmol/L. This value is significantly elevated.

Concept Tested & Keywords

Concept Tested: Interpretation of laboratory values in sepsis
Stem keywords: Sepsis, ICU, laboratory value, abnormal
Lead-in keywords: Which
Clinical cues: Patient has sepsis, which directs focus to specific markers of organ dysfunction.

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E6 Medicine Macleod Clinical Examination 15e p. 399-401

E6 Nursing Fundamentals Potter Perry 12e Part 2 p. 225-227

Practise the full NORCET 8 Prelims-2025

Attempt every question from this paper in a timed mock, then review the full solution for each one.