Abnormal H Flag Next to Platelets Result, what does that mean?

When you receive the result of the test ” full blood count” at the laboratory, you will surely find the result of the “platelet count” near the middle of the formatted CBC report.


Like all types of labs, there is “the name of the test” on the left side, and “the result” that the laboratory found after analyzing is written in the middle of the report, while the right side is dedicated to writing the details of “the required levels” or what is called “the reference range”, other test may have “the normal range” instead, do you know the difference? Go there to learn more about “reference ranges of labs“.

However, what is written to the right of the CBC test report is the reference range, the two-limits range that the patient’s result measured compared to that range.

How do you read a platelet count with H letter?

If the result of the patient’s is a number from within the reference range limits, we say that the result is considered normal and thus there’s no need to type the abbreviation “N” next to it, and if the result is higher than the upper limit of the normal range, we say the result is high, and a notation is placed in the form of a letter H as an abbreviation for the word high, and therefore, if the result is less than the minimum limit of the normal range, this definitely means that your result is low and the letter L is written next to it as an abbreviation of the word low platelets, that is the way in which the laboratory expresses the increase or decrease in your test results.

The normal platelets range (concentration” in the human blood is 140 thousand to 450 thousand cell per each microliter of blood, slightly variable according to age and gender.

What is platelet count H?

And therefore, the H letter next to platelet value means that you have too much number of platelets than the upper required value (450,000) of the normal human platelet count, the high platelet level means “thrombocythemia” or generally named “thrombocytosis”.

However, H is a sign of “abnormal platelets count” and does not represent the abnormal morphology of platelets because the shape of blood platelets can be measured by other tests including examination of blood film and platelet aggregation test.

By the way, the platelets may be abbreviated “PLT” in most CBC test results, that’s to know the meaning of “PLT” shortcut in your labs.

Example for h flag next to platelets

In the opposite, read about the meaning of PLT L flag.

Causes of elevated platelets level than normal range are a health issue that may be caused by another disease or primary a platelet disease, and that is another explanation, please follow for more details.

The benefits of writing H notation beside the platelet count including: easing the reading of platelet result in the lab test instead of writing many words, help the ordinary people to understand their platelets levels and therefore, you may not need a specialized doctor or any of the medical staff to read your simple numbers in a lab test.
However, extremely elevated platelets number doesn’t have specific flag other than the “H” letter, it doesn’t differentiate the degree of increased platelets “thyrombocytosis”, and the best action is to revise the madly high results with a well-experienced doctor or you may messaging us to guide you.

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