MCH stands for Mean Corpuscular Haemoglobin, which is a protein that aids in the delivery of oxygen throughout the body. An MCH test is a diagnostic blood test used for assessing the overall health of a person by measuring MCH levels in the blood. 

Although MCH and MCHC (Mean Corpuscular Haemoglobin Concentration) blood tests are two serological tests with a similar interpretation of their levels in the body, signifying the health of haemoglobin in the blood, both are not the same thing. While the MCH level refers to the haemoglobin in each red blood cell, MCHC is the average weight of that haemoglobin based on the volume of red blood cells.

What is an MCH blood test? 

An MCH blood test is a diagnostic test recommended by a healthcare provider, which is conducted as a part of a blood test called a complete blood count (CBC). The CBC test evaluates the composition of the blood, checking the amount of red blood cells (RBCs), white blood cells (WBCs), and platelets in a blood sample. The CBC test helps provide an overview of a person's general blood health.

MCH levels in the blood are measured in picograms (pg). The normal range of MCH levels in an MCH blood test ranges between 26 to 33 pg of haemoglobin per red blood cell in adults.

Purpose of the MCH blood test

The MCH blood test helps determine the average amount of haemoglobin contained in the blood. It is not measured directly; MCH is based on the haemoglobin level (Hg), which represents the total amount of haemoglobin present in the blood. The level of MCH, as measured by the CBC test, can help identify a range of problems in the body, varying from conditions of nutrient deficiency (such as anaemia) to chronic conditions within the body.

How is an MCH done?

An MCH blood test may be performed as part of a complete blood test. A phlebotomist may collect a blood sample, which is then tested in a laboratory based on its parameters. To calculate the MCH level, the amount of haemoglobin is divided by RBC count. This calculation yields an average amount of haemoglobin per red blood cell. 

What do High MCH Levels mean?

MCH levels over 34 pg in an MCH blood test can be considered high. A high MCH value is most commonly attributed to macrocytic anaemia, a blood disorder that leads to the production of fewer red blood cells than normal. Consequently, the red blood cells are larger than usual and carry more haemoglobin than a normal RBC would. This condition is caused by a deficiency of vitamin B12 (or folic acid) in the body.

When does the doctor recommend an MCH Test?

A doctor may recommend an MCH test during a routine checkup or to evaluate a specific health problem related to a blood disorder, such as anaemia.

What are the symptoms of High MCH Levels?

People suffering from macrocytic anaemia may experience symptoms that gradually worsen over time. These symptoms may include:

• Fatigue
• Paleness of the skin
• Faster heartbeats
• Brittle nails
•  Poor concentration
•  Confusion and memory loss

There can be additional symptoms of high MCH levels in the blood, such as:

• Nausea or vomiting
• Bloating
• Diarrhoea
• Irritability
• Decrease in appetite
• Having a tingling sensation in the hands and feet
• Smoothness or sensitivity on the tongue

MCH Results & Normal Range 

To interpret the MCH levels in a sample appropriately, the results need to be compared to the given reference range of the laboratory test. The MCH levels are measured in picograms (pg). When the amount of MCH falls outside of the given reference range, it can indicate that the amount of haemoglobin in the RBCs is too low or too high. Sometimes, even if the MCH level falls within this range, there can still be an underlying health condition which can be diagnosed with help from the results of other blood test indices.

Although different laboratories may have different parameters for measuring MCH pg levels in a blood test, the normal MCH level usually ranges between 26 and 33 picograms. The reference range and abnormal ranges have been provided below for comparison. 

What can cause High MCH Levels?

A high level of MCH is mostly due to vitamin B12 deficiency. There can also be other causes of high levels of MCH, which may include the following conditions:

• Liver diseases
• Overactivity of the thyroid gland
• Regular alcohol consumption
• Regular use of oestrogen medications
• Complications from infection and/or cancers

What should I do if I have High MCH Levels?

High MCH levels in blood, as a result of macrocytic anaemia or other underlying conditions, may be treated differently in different patients based on their symptoms and the severity of the condition. Adding more vitamin B12 to the diet can help improve this condition. This can be done by eating foods like fish, liver, green leafy vegetables, and fortified cereals. These contribute to a higher efficiency of red blood cell production. Other conditions contributing to high MCH levels can be treated with appropriate measures as decided by the treating doctor.

Conclusion

Mean corpuscular haemoglobin is an important health indicator among other factors. It is usually measured during a routine blood test or when a doctor suspects anaemia based on a patient's symptoms. Imbalances in MCH levels can be managed by maintaining a healthy diet and including the necessary nutrients. A proper recovery diet plan can be designed by consulting a registered dietitian. Regular blood tests can reveal changes or improvements in the conditions affecting patients due to the imbalance of MCH levels in their bodies.

FAQs

1. What is meant by low MCH levels in a blood test?

Ans. MCH levels below 26 picograms can be considered as low and can be due to a number of reasons associated with red blood cells such as excessive blood loss, iron deficiency, and microcytic anaemia.

2. What is the cost of an MCH test?

Ans. An MCH test is performed as a part of a complete blood count (CBC) test and may cost around Rs. 70 to Rs. 150.

Reference:
https://www.medicalnewstoday.com/articles/318192#What-is-MCH
https://www.webmd.com/a-to-z-guides/what-are-mch-levels
https://www.testing.com/itests/mch-test/#:~:text=The%20MCH%20test%20 is%20 one,and%20issues%20in%20the%20body.