Raj. CHO -2020: What is used to measure the amount of Hemoglobin?

Raj. CHO -2020

Biochemistry & Nutrition

Easy

Appeared in: Raj. CHO -2020

Explanation

N/10 HCl (Hydrochloric acid) is the specific reagent used in the Sahli's acid hematin method for estimating hemoglobin.
This acid lyses the red blood cells to release hemoglobin.
It then converts the iron in hemoglobin into a stable, brown-colored compound known as acid hematin.
The concentration of hemoglobin is determined by diluting this solution with distilled water until its color visually matches a standard brown glass comparator.

Option A: NaCl (Sodium Chloride) is common salt. In medicine, it's primarily used to prepare isotonic saline solutions for intravenous infusions or as a diluent. It does not have the chemical properties to convert hemoglobin into a measurable colored compound.
Option C: NaOCl (Sodium Hypochlorite) is the active ingredient in bleach. It is a powerful disinfectant and oxidizing agent that would denature and destroy the hemoglobin protein, making any measurement impossible.
Option D: NaOH (Sodium Hydroxide) is a strong alkali or base. While an 'alkaline hematin' method for hemoglobin estimation exists, it is less common and uses a different principle. The standard and widely known Sahli's method is an 'acid hematin' method, which specifically requires an acid like HCl.

Visual 1: Diagram: Sahli's hemoglobinometer, illustrating the comparator with standard brown glass rods, the graduated Sahli's tube, and the pipette for measuring blood.
Visual 2: Flowchart: A step-by-step visual guide of the Sahli's method, from adding blood to HCl to the final color matching and reading.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Reagent for Hemoglobin Estimation (Sahli's Method) as background academic context rather than a clinical decision trigger.
Hemoglobin measurement is a fundamental component of a complete blood count (CBC) and is essential for diagnosing and managing anemia and polycythemia.
Nurses frequently monitor hemoglobin levels to assess a patient's response to treatment (e.g., iron supplements, blood transfusions) and to evaluate blood loss after surgery or trauma.
Normal hemoglobin ranges are crucial to know: Males (14–18 g/dL) and Females (12–16 g/dL). Values below these ranges indicate anemia.

How to Approach the Question

First, identify the core of the question, which asks for the specific chemical used to measure hemoglobin.
Recall the common manual laboratory methods for hemoglobin estimation. The Sahli's method is a classic technique often taught in basic nursing and medical laboratory courses.
Remember the principle of the Sahli's method, which is also known as the 'acid hematin' method.
The name 'acid hematin' is a strong clue that an acid is required. Look for an acid among the options.
N/10 HCl is hydrochloric acid. The other options are a salt (NaCl), a bleach (NaOCl), and a base (NaOH).
Select N/10 HCl as it is the only acid and directly corresponds to the principle of the Sahli's method.

Concept Tested & Keywords

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E6 Biochemistry U Satyanarayana 7th Edition — Part 1 (pp 26-420 of 840) p. 256-266