Sahil Method: Principle, Procedure & 7 Advantage

Sahil method is also known as the acid hematin method. The Sahil method was first introduced by Sir Hermann Sahli in 1856. This is a type of visual method or colorimetric method that helps in the estimation and determination of hemoglobin.

Principle: Sahil method

When the whole blood is diluted into the blood is mixed with a strong hydrochloric acid. The hemoglobin breaks down and is converted to brown color acid haematin. This is then diluted with water till the brown color matches that of the brown glass standard. The hemoglobin value is read directly from the scale. In the second word, blood is mixed with N/10 HCl resulting in the conversion of Hb to acid hematin which is brown. The solution is diluted till its color matches the brown colored glass of the comparator box. The concentration of Hb is read directly.

How many methods for hemoglobin estimation

Estimating hemoglobin levels is a crucial aspect of assessing an individual’s health, especially in the context of conditions such as anemia or other blood disorders. There are several methods used for the estimation of hemoglobin, each serving specific purposes in clinical settings. Here are some common methods:

Hemoglobin Color Scale Method: This is a simple and cost-effective method commonly used in resource-limited settings. A drop of blood is placed on a special filter paper, and the color change is compared to a standardized color chart. Each color corresponds to a specific hemoglobin concentration.

  • Sahil Method
  • Wintrobe Method
  • Dare Method
  • Haden Method

Cyanmethemoglobin Method: Widely used in clinical laboratories, this method involves converting hemoglobin to cyanmethemoglobin, a stable compound. The intensity of the resulting color is then measured spectrophotometrically, and the hemoglobin concentration is determined based on the absorbance.

Hemoglobin Electrophoresis: This method separates different types of hemoglobin based on their electrical charge. It is particularly useful for identifying abnormal hemoglobin variants, such as those seen in certain genetic disorders like sickle cell anemia.

Hemoglobinometer: Hemoglobinometers are portable devices that use a colorimetric method to estimate hemoglobin levels. A blood sample is mixed with a reagent, and the color change is matched to a color scale to determine the hemoglobin concentration.

Automated Hematology Analyzers: Modern laboratories often employ automated hematology analyzers that use advanced technology to provide a complete blood count, including hemoglobin levels. These analyzers use a combination of methods, such as flow cytometry and spectrophotometry, for accurate measurements.

Material Required For Sahil Method

  • Sahli haemoglobinometer: This is an instrument.
  • Two Pasteur pipettes (one for HCl and one for distilled water).
  • Glass rod to stir ( stirrer ): This is a glass rod utilized for stirring the mixture within the hemoglobin tube.
  • 0.1 N – Hydrochloric acid(HCI): This is a reagent.
  • Distilled Water: Distilled water is water that has been heated to the point of vaporization and then condensed back into liquid form in a separate container.
  • Comparison tube.
  • Pipette ( Hemoglobin pipette with rubber tubing and mouthpiece )
  • 0.5% chlorine solution.

Sahil Method procedure

  1. Keep all necessary items ready (Sahli Hb meter, N/10 HCl, gloves, spirit swabs, lancet, distill water and dropper, puncture-proof container, 0.5% Chlorine solution ) Cleans the Hb tube and pipette.
  2. Wash hands and wear gloves.
  3. Fill the Hemog;obin tube with N/10 hydrochloric acid up to 2 gm with the dropper and place it in the Hb meter
  4. Clean the tip of the person’s ring finger with a spirit swab.
  5. Prick the finger with a lancet and discard the first and second drops of blood.
  6. Allow a large blood drop to form on the fingertip and sucks it with a pipette up to the 20 cm mark. Ensure that air entry is avoided while drawing blood.
  7. Wipe the tip of the pipette and transfer the blood to the Hb tube containing N/10 hydrochloric acid.
  8. Rinse the pipette 2-3 times with N/10 hydrochloric acid.
  9. Leave the solution in the hemoglobin tube for 10 minutes.
  10. After 10 minutes, dilute the acid by adding distilled water drop by drop and mix it with a stirrer.
  11. Record the reading (lower meniscus) when the color of the solution precisely corresponds to that of the comparators on both sides of the Hb Meter.
  12. Rinse the Hb tube 2-3 times with N/10 HCl and dispose of the used lancet in a puncture-proof container.
  13. Drop the used gloves in 0.5% Chlorine solution.

Advantages and Disadvantages of the Sahil Method

Advantage of Sahil Method:-

  • Very easy to perform
  • Very low cost
  • Low time-consuming. It will take only 15-20 minutes
  • At the same time, you can do another work
  • Not require any kind of electricity connection
  • Regents are not harmful
  • Not require any technical expert for this

Disadvantage of Sahil Method:-

  • Less accurate in comparison to other methods.
  • All hemoglobins (oxyhemoglobin, sulphemoglobin) will not converted to acid hematin, and the value of Hb obtained is less than the real value.
  • The color of acid hematin develops very slowly.
  • Variation in the matching of color is seen.
  • Color of glass standards may fade over time.

Physiological Significance Of Sahil Method:

  • Determination of Hb concentration is used for diagnosis of anemia and polycythemia or any disease related to them.
  • Polycythemia
  • Hemoconccentration
  • Dehydration
  • Decrease less than normal:
  • Anemia
  • Hemodilution
  • Hydration
Normal values in different species:
  • In Male 14-18 (g/dl)
  • In Females 12-16 (g/dl)
  • Dog 12-15 (g/dl)
  • Horse 13-15 (g/dl)
  • Cattle 11-12 (g/dl)
  • Sheep 10-11 (g/dl)
  • Goat 10-11 (g/dl)
  • Pig 12-14

different types of hemoglobin

Hemoglobin, the essential protein in red blood cells responsible for oxygen transport, exists in various types or forms. Each type has distinct characteristics and functions. Here, we explore the different types of hemoglobin:

  1. Hemoglobin A (HbA)
  2. Hemoglobin A2 (HbA2)
  3. Hemoglobin F (HbF or Fetal Hemoglobin)
  4. Hemoglobin S (HbS)
  5. Hemoglobin C (HbC)
  6. Hemoglobin E (HbE)

1. Hemoglobin A (HbA):

  • Dominant Form: Hemoglobin A is the predominant and normal adult hemoglobin.
  • Structure: It consists of two alpha-globin and two beta-globin protein chains.
  • Function: HbA efficiently carries oxygen from the lungs to body tissues and helps transport carbon dioxide back to the lungs for elimination.

2. Hemoglobin A2 (HbA2):

  • Presence: Hemoglobin A2 is a minor component, constituting about 2-3% of adult hemoglobin.
  • Structure: It is composed of two alpha-globin and two delta-globin chains.
  • Significance: Hemoglobin A2 is particularly relevant in the diagnosis of certain types of thalassemia, a genetic blood disorder.

3. Hemoglobin F (HbF or Fetal Hemoglobin):

  • Presence: Predominant in fetuses, Hemoglobin F decreases after birth, making up a small percentage in adults.
  • Structure: Composed of two alpha-globin and two gamma-globin chains.
  • Function: HbF has a higher affinity for oxygen, facilitating oxygen transfer across the placenta from the mother to the developing fetus.

4. Hemoglobin S (HbS):

  • Genetic Variation: Hemoglobin S results from a genetic mutation, causing a change in the beta-globin chain.
  • Associated Condition: HbS is linked to sickle cell disease, a genetic disorder where red blood cells assume a rigid, sickle-like shape, leading to various health complications.

5. Hemoglobin C (HbC):

  • Genetic Variation: Hemoglobin C is another variant resulting from a genetic mutation in the beta-globin chain.
  • Characteristics: Individuals with Hemoglobin C may have mild anemia and altered red blood cell shape, but the condition is generally less severe than sickle cell disease.

6. Hemoglobin E (HbE):

  • Genetic Variation: Hemoglobin E is a variant caused by a genetic mutation in the beta-globin chain.
  • Geographical Prevalence: Common in certain regions, especially in Southeast Asia.
  • Clinical Significance: Hemoglobin E trait or disease may impact red blood cell function and contribute to anemia.

Understanding the different types of hemoglobin is crucial for diagnosing and managing various blood disorders. Each variant has its unique characteristics, and their presence or absence can provide valuable insights into an individual’s health and potential genetic conditions.

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Q: What is the normal range of hemoglobin in adults?

A: The normal range for hemoglobin in adults varies, but it’s generally between 12 to 16 grams per deciliter (g/dL) for women and 13.5 to 17.5 g/dL for men.

Q: Can low hemoglobin levels lead to health problems?

A: Yes, low hemoglobin levels can result in anemia, causing fatigue, weakness, and shortness of breath. It’s essential to identify and address the underlying causes.

Q: How is hemoglobin measured in a blood test?

A: Hemoglobin is typically measured through a blood test, and the most common methods include the Sahli method, cyanmethemoglobin method, and automated hematology analyzers.

Q: What is thalassemia, and how is it related to hemoglobin variants?

A: Thalassemia is a genetic blood disorder characterized by abnormal hemoglobin production. Hemoglobin variants, such as Hemoglobin A2, are often used in the diagnosis of thalassemia.

Q: What is sickle cell disease, and how does it relate to hemoglobin S?

A: Sickle cell disease is a genetic disorder where Hemoglobin S causes red blood cells to assume a sickle shape, leading to various health complications, including pain, anemia, and organ damage.

Q: Can hemoglobin variants be inherited?

A: Yes, many hemoglobin variants, including those associated with thalassemia, sickle cell disease, and others, are inherited genetically from parents.

Q: Are there specific populations more prone to certain hemoglobin variants?

A: Yes, certain hemoglobin variants like Hemoglobin E are more prevalent in specific geographical regions, such as Southeast Asia.

Q: How is fetal hemoglobin (HbF) different from adult hemoglobin?

A: Fetal hemoglobin (HbF) has a higher affinity for oxygen and is the predominant type in fetuses. It gradually decreases after birth as adult hemoglobin (HbA) becomes dominant.

Q: Can hemoglobin variants affect overall health?

A: Yes, depending on the variant, it can impact overall health. Conditions like sickle cell disease and thalassemia may require careful management and medical attention.

Q: Is there a cure for genetic blood disorders related to hemoglobin?

A: While there’s no universal cure, medical treatments and interventions can help manage symptoms and improve the quality of life for individuals with genetic blood disorders related to hemoglobin.

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