High or low platelet count: causes and what to do

What platelets are and what’s normal

Platelets are tiny cell fragments made in the bone marrow. When a blood vessel is damaged, they stick to its wall, clump together and, with clotting proteins, seal the wound. A platelet lives for about 7–10 days, so the bone marrow keeps making new ones, and the count can change within a few days.

On a complete blood count, platelets are labeled PLT. For adults, doctors go by a range of 150–400 ×10⁹/L. Some analyzers print the result in thousands per microliter, and 150–400 K/µL means the same thing. If your result is slightly outside the reference range, the doctor will interpret it together with your other results.

Why is my platelet count high?

Most often, platelets rise in response to something going on in the body. This is called a reactive rise, and it happens:

• during and after an infection;
• with inflammation, for example rheumatoid arthritis or inflammatory bowel disease;
• after an injury, surgery or bleeding;
• with iron deficiency;
• after the spleen has been removed, because it normally holds back some of the platelets.

Once the cause is gone, platelets gradually return to their usual level. That’s why the doctor often suggests repeating the test after a few weeks and checks your iron stores with a ferritin test at the same time.

Less often, high platelets are caused by a bone marrow disorder in which the marrow makes too many cells. Then the count stays high for months with no visible reason, and other blood values are sometimes abnormal too. These conditions raise the risk of blood clots, so the doctor will always investigate a persistently high platelet count with no clear cause. If your platelets are over 1000 ×10⁹/L, show the result to a doctor within the next few days: at this level, doctors usually don’t wait for a repeat test and consult a hematologist.

Don’t start taking blood thinners on your own. With very high platelets they can increase the risk of bleeding, so whether you need them is your doctor’s decision.

Why is my platelet count low?

First, the doctor checks whether the drop is real. In some people, platelets clump together in the tube with an anticoagulant (a substance that stops blood from clotting), and the analyzer counts fewer than there actually are. The person feels well and has no bruises. To check this, the test is repeated, sometimes in a tube with a different anticoagulant, or a blood smear is examined under a microscope.

A true drop most often has one of these causes:

• viral infections, from a cold or flu to hepatitis;
• certain medicines;
• alcohol, which suppresses platelet production;
• liver disease, in which an enlarged spleen holds on to platelets;
• immune thrombocytopenia, when the immune system destroys its own platelets: in children it often follows a viral infection and usually goes away on its own, while in adults it is more likely to persist;
• pregnancy: it’s not unusual for platelets to drop slightly in the second half of pregnancy and recover after delivery, and the doctor monitoring you assesses this;
• a lack of vitamin B12 or folate.

Less often, the cause is a bone marrow disorder. Then hemoglobin or white blood cells are usually abnormal too.

What are the signs of low platelets?

With more than 50 ×10⁹/L, most people notice nothing. As the count falls further, you may see:

• bruises from a light bump or for no reason at all;
• tiny red or purple spots on the skin, often on the shins, that don’t fade when you press on them;
• bleeding gums and nosebleeds;
• heavier and longer periods than usual;
• bleeding from a cut that takes a long time to stop.

The risk of bleeding without an injury rises noticeably when the count falls under 20 ×10⁹/L.

What to do if your platelet count is abnormal

Don’t treat yourself, and don’t worry over a single result. Show your test to an internist or family doctor: they’ll look at your platelets together with hemoglobin, white blood cells and your symptoms and tell you when to repeat the test. For tips on how to prepare, see the article on the complete blood count.

See a hematologist if your platelets stay abnormal on repeat tests or are far outside the normal range, or if other blood values are also abnormal or your lymph nodes are swollen. The Viva Clinic hematologist sees patients at 27a Sobornosti St or 3 Danyla Halytskoho St; the exact address is confirmed when you book. You can book a hematologist consultation by phone or on Viber. You don’t need a referral, and the consultation is paid. The hematologist will help with the tests you need and, if you need treatment at a specialist hematology center, give you a referral.

See a doctor the same day if your platelets are under 20 ×10⁹/L, even if nothing is bothering you, or if new bruises and spots are quickly appearing on your skin. Call an ambulance (103) if bleeding won’t stop, there’s blood in your urine, stool or vomit, you suddenly get a severe headache, or your vision or speech is affected. Also call 103 if spots on your skin appear together with a high temperature.