What is IDH in Blood Tests and Why is it Important?

a lab worker doing a idh blood test in a laboratory

Isocitrate dehydrogenase, or IDH, is an enzyme that plays a major role in the oxidative decarboxylation of isocitrate in the Krebs cycle. The end product is carbon dioxide and alpha-ketoglutarate.

Recent studies have revealed that IDH mutations indicate the occurrence of glioma. Hence, it is essential to have oneself screened.

This article talks about IDH in blood tests, when to perform it, and its importance in blood tests, among other details.

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What does IDH in Blood Tests Indicate?

The IDH1 gene is responsible for the production of isocitrate dehydrogenase. When anyone develops a brain tumour, the IDH1 gene undergoes a mutation, which is consequently revealed in the blood test. Any kind of malignancy in the glial tissue shows a mutation in IDH1.

The analysis of the blood tests helps diagnose specific types of brain tumours, such as secondary glioblastoma, oligodendroma, or oligoastrocytoma. The symptoms of IDH mutation include retarded brain function, nausea, vomiting, memory loss, and vision problems.

What is the Importance of IDH in Blood Tests?

The IDH blood test is done to evaluate the following health conditions:

Ollier Syndrome: It is a rare disorder of the bones recognized by the abnormal development of bones. Even though it is a congenital defect, the symptoms are seen in early childhood.
Oligodendroglioma: It is a type of CNS tumour that accounts for nearly 5% of intracranial tumours. They are generally treatable through surgery, even in malignant conditions.
Acute Myeloid Leukaemia: Acute Myeloid Leukaemia is a rare type of blood and bone marrow cancer that can progress fast. It can turn out to be life-threatening if not treated on time.
Astrocytoma: Astrocytoma is a malignant tumour developing in the brain or spinal cord. They originate from the star-shaped astrocytes in the CNS. In some cases, they grow aggressively, while in some, they take months to grow.
Maffucci Syndrome: It is a lesser-known genetic disorder of the cartilage characterised by benign tumours in the cartilage, mainly seen in the hands. The symptoms may include pain and skeletal abnormalities.

When to Test for IDH in Blood Tests?

Seek medical help whenever you go through the symptoms of brain tumours. If your physician considers you fit for the test, they will order you to take the test. However, before taking the test, you follow the instructions below:

Fix an Appointment: Consult a diagnostic centre having this facility and fix an appointment at your convenience. This might be a bit expensive as only some labs offer this service.
Food: Usual meals can be continued unless other tests are added along with IDH tests. Fasting is optional if only the IDH test is to be done. Consult your physician in case of any queries.
Exercise: People undergoing strenuous exercise may avoid it before the test as it may impact the results. Also, heavy workers may put a pause on it before the test.
Drugs and Medications: Tell your physician about the existing medications, as consumption of medicines may alter the test results. Your physician will inform you of any kind of modification in medication.

How to Test for IDH in Blood?

Go through the following steps to prepare for an IDH blood test:

Step 1: Visit the concerned lab and fill out the test form.
Step 2: Your healthcare provider will take you to the test.
Step 3: Roll up your sleeves and expose the elbow bend from where the blood will be drawn.
Step 4: The healthcare provider will tie a tourniquet and prick a needle in the desired vein to draw blood.
Step 5: After collecting enough in the vial, they will untie the tourniquet and remove the needle.
Step 6: Put a cotton ball over the pricked area if the bleeding does not stop and you are done.

Apart from blood tests, Isocitrate Dehydrogenase can also be assessed with the help of bone marrow aspirate and tissue biopsy. The side effects of the test may include pain and infection at the puncture site, bleeding, or thrombophlebitis.

What are the Normal Values for IDH in Blood Tests?

The average value of IDH1 in blood for all age groups and genders is less than 1000kU/litre.

IDH is a component of the Krebs cycle, which catalyses an irreversible reaction. Hence, it is imperative to regulate the enzyme. Any kind of mutation can result in life-threatening brain tumours. Out of all the isoforms of IDH, IDH1 is of most importance.

FAQs about IDH in Blood Tests

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What does IDH1 positive mean?

A positive IDH1 result means that the individual has undergone a mutation in the IDH1 gene. It is a biomarker that tells us about glioma in brain tumours.

What is the most common IDH1 mutation?

The most common IDH1 mutation is R132H, which changes arginine to histidine and is seen in most gliomas.

What is the difference between IDH1 and IDH2?

IDH1 and IDH2 have the same function but differ in cellular localizations and physiological roles.

What is the cost of undergoing an IDH blood test?

The cost of an IDH (Isocitrate Dehydrogenase) blood test can vary depending on the diagnostic lab, city, and whether the test is conducted as part of a broader diagnostic panel. On average, it may range from ₹2,000 to ₹6,000 or more.

The good news is that many health insurance plans can help cover these costs if the tests are medically necessary and you have opted for OPD cover in insurance.