The hematocrit is an important test for estimating the average volume of red blood cells. Anticoagulated blood is used for hematocrit tests.

You can calculate mean corpuscular volume (MCV) with the help of HCT.

Manual hematocrit calculation methods

There are two methods for calculating the hematocrit.

1. Macro Method (Wintrobe’s Method)
2. Micro Method

Wintrobe’s method of Hematocrit (macrohematocrit) test requirements, procedure , advantage and disadvantage

It is an old method of HCT estimation, now the micro method is used.

Test Requirements

1. Wintrobe tube
2. Centrifuge (15 cm internal radius)
3. Pasture pippet

MacroHematocrit testing Procedure

1. Fill the tube up to the maks of 100 with EDTA anti-coagulated blood.
2. Centrifuge the tube at 3500 rpm for 30 minutes.
3. Carefully take the tube from the centrifuge and note the level of packed RBC (Buffy coat should not be included).

Note: If packed cell volume is above the 0.5 L/L, centrifuge again for 30 minutes.

Advantage of macrohematocrit method

• The same tube can be used for ESR (Erythrocyte Sedimentation Rate)
• It did not require a special centrifuge as micro mrethod.

DisAdventage macrohematocrit method

1. The macro method requires a large amount of blood as compared to the micro method.
2. Centrifugation time is long (30 mint).
3. This method is not 100% accurate.

Microhematocrit method procedure, requirements, procedure , advantage and disadvantage

It is an advanced method of hematocrit calculation.

Requirements

1. 75 mm length with 1 mm bore longe tube.
2. Microheamtocrit centrifuge
3. Microhematocrit Reader
4. Plasticine

Microhematocrit method Procedure

1. Fill the tube with blood.
2. Seal one end of the tube with plasticine.
3. Place the tube in the Microheamtocrit centrifuge.
4. Centrifuge for 4 to 5 minutes.
5. Take the tube from the centrifuge and place it in the microhematocrit Reader and note the packed cell volume (PCV).

Advantage of microhematocrit method

1. Small quantity is sufficent for the test (Macro method need large).
2. Less centrifuge time is requiered in micro-method.
3. One than one sample can be run at a time.
4. It is accurate as compare to Macro method.

DisAdventage of microhematocrit method

• It needs Microhematocrit Reader.
• Microheamtocrit centrifuge is necessary for the micro method.

Sources of error in Hematocrit test (PCV/ HCT)

1. Sample collecting error.
2. Incorrect amount of anti-coagulant.
3. Incorrect filling of the tube.
4. A clot in the sample.
5. Hemolysis sample.
6. Variation in the internal diameter or bore of the tube.

Give the possible variations in color of the plasma when performing hematocrit determination.

During hematocrit determination, the color of the plasma can vary based on several factors. Here are some possible variations:

• Pale or Straw-Colored: This is the typical color of normal plasma. It appears pale yellow or straw-colored.
• Pink or Reddish: If there is hemolysis (breakdown of red blood cells), the plasma may have a pink or reddish tinge. This can occur due to factors such as rough handling of the sample or certain medical conditions.
• Cloudy or Milky: In some cases, the plasma may appear cloudy or milky. This can be caused by increased lipid levels (lipemia) in the blood, which can occur after consuming a fatty meal or in certain medical conditions.
• Yellow or Jaundiced: If there is an excessive amount of bilirubin in the blood, the plasma can have a yellowish tinge. This is commonly seen in conditions such as jaundice or liver disease.