The normal platelet count in human blood is about:

OSSSC Nursing Officer-2021

Applied Physiology

Easy

Appeared in: OSSSC Nursing Officer-2021

Explanation

Platelets, or thrombocytes, are essential for blood clotting and wound healing.
The normal range for platelets in a healthy adult is widely accepted as 150,000 to 450,000 per cubic millimeter (mm3) or microliter (μL) of blood.
The option 150,000-350,000/mm3 falls squarely within this established normal range, representing a healthy count for effective hemostasis.
Counts outside this range can indicate either a bleeding risk (thrombocytopenia) or a clotting risk (thrombocytosis).

Option A: This range (70,000-90,000/mm3) is below the lower limit of normal, indicating moderate thrombocytopenia, which poses a risk of bleeding.
Option C: The lower end of this range (50,000/mm3) is critically low and signifies severe thrombocytopenia, which carries a high risk of spontaneous bleeding. A normal range cannot include such a low value.
Option D: This range (4,000-11,000/mm3) represents the normal count for White Blood Cells (WBCs), which are part of the immune system, not platelets.

Clinical Relevance

Nursing practice connection: Knowing Normal laboratory values - Platelet count helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must be familiar with normal platelet counts to identify patients at risk for bleeding or clotting. This is crucial for pre-operative assessments, monitoring patients on chemotherapy (which can cause bone marrow suppression), and managing patients with hematological disorders.
A low platelet count (thrombocytopenia) requires implementing bleeding precautions, such as using a soft toothbrush, avoiding IM injections, and monitoring for signs of bleeding like petechiae, ecchymosis, or hematuria.
A high platelet count (thrombocytosis) may require monitoring for signs of thrombosis, such as calf pain (DVT), chest pain (PE), or neurological changes (stroke).

How to Approach the Question

First, identify the core of the question, which is asking for a specific, factual piece of information: the normal range for a lab value (platelet count).
This is a 'Recall' type question. Your task is to retrieve this specific value from your knowledge base.
Scan the options provided. Notice the different numerical ranges and units (per mm3).
Recall the normal ranges for the main components of a Complete Blood Count (CBC). Platelets are typically in the hundreds of thousands.
Evaluate each option against the recalled normal range. Option A is too low. Option D is the range for WBCs. Option C starts too low.
Select the option that most accurately reflects the established normal physiological range. Option B (150,000-350,000/mm3) is the standard range taught and used in clinical practice.

Concept Tested & Keywords

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E6 Physiology Essentials Sembulingam 10e Part 1 p. 131-133

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 811-813