Briefly, the number of platelets in the blood test may increase as a result of the increase in red blood cells in the complete blood picture test which is called polycythemia by medical doctors.
Although the Polycythemia vera disease (PV) is a rare disease, meaning that it is not necessary that all people whose complete blood count contains elevated red blood cells will be affected by polycythemia, it may occur to an almost noticeable degree. Polycythemia is producing more red blood cells than required, which may cause adverse results instead of being beneficial. In this post I'm going to focus on the effect of polycythemia on the count of platelets in CBC test and the reasons behind that along with how to read and understand your lab result?
What labs are abnormal with Polycythemia vera?
If you were a patient with Polycythemia vera, you may wondered; what may I see in my lab test results? below are some examples of blood test results that may accompany PV:
- The number next to RBC count is higher than the normal range that recorded in the laboratory report.
- Hemoglobin level is high or at the last degree of the upper normal limit. (This is the opposite of anemia in which hemoglobin appears low). PV indicated when Hemoglobin levels greater than 16.5 g/dL in women and above 18.5 g/dL in men.
- Hematocrit (HCT or PCV) is high, HCT represents the percentage of whole red blood cells to the whole size of blood sample, i.e. HCT or PCV stands for "the Packed Cells Volume". If PCV is greater than 48 in women and above 52 in men, it usually indicate Polycythemia.
- Normal MCV (Normocytes) or Low MCV (Microcytosis) , Low MCH and MCHC (Hypochromia) or may be normal (Normochromic).
- High count of blood platelets above the normal level in most patients (Reactive Thrombocytosis).
- Abnormal PDW and MPV, they help doctors know what is the estimated average size of platelets?.
- Blood smear examination may reveal "Rouleaux formation" which may lead to clogs of blood vessels, thus blood clot formation.
- White blood cells (WBCs) are also higher than normal especially those named "Neutrophils" (in medical terms, Leukocytosis and Neutrophilia)
- Erythropoietin hormone is lower than normal, it's the hormone stimulates Bone marrow (BM) for RBCs production.
- ESR test may be mildly elevated or still normal during high PLTs and RBCs.
- Abnormal Kidney function tests, high or normal creatinine with normal or high BUN.
You may need to know what's normal platelets level for your age and gender?
What happen to platelets in Polycythemia vera disease?
By looking at the medical textbooks, the causes of polycythemia can be divided into three main pathways:
The first, includes physiological causes (non-pathological) such as thirst, dehydration, and also includes some respiratory diseases, such reasons can cause the volume of the fluid portion in the blood (plasma) to decrease, and thus the ratio of the part that contains blood cells becomes greater (Packed cells volume), which appears in blood count tests as "hematocrit, HCT" and therefore doctors call this type the "normal, or relative polycythemia", and this type may not cause any effect on blood platelets, i.e. the platelets count results still appear inside the two normal limits (140-450), therefore, it is common in cases of dehydration that the platelet count in your CBC test be normal or at a level closer to the upper limits of the normal level "Example: 395,000".
Relative polycythemia is transient and can be resolved within few hours to few days.
The second pathway, which includes the occurrence of a specific disease that affects the level of the hormone erythropoietin, this hormone is the one produced by the kidneys cells to stimulates the bone marrow to produce the required number of red blood cells only which means that it has no medically known relationship with the rest of the blood cells”, therefore, high erythropoietin will increase the RBCs count only and will not affect platelets count or WBCs. Thus, PV that comes from these pathological causes has little effect on the normal level of platelets in the CBC test results (e.g. 250,000), but of course the occurrence of any other disease may cause a change in the level of platelets, examples of these diseases: Renal tumors that cause an increase in the erythropoietin hormone.
The third pathway is the one that caused by a mutation in the gene responsible for guiding bone tissue in the process of original cells replication to form red blood cells, white blood cells and platelets, which they are the "myeloid and megakaryocytes", thus the mutation causes the bone marrow to produce a very large number of blood cells without the need for them and without limitations, meaning that the body and bone marrow are unable to stop the replication of cells in this crude way, and therefore you may see the complete blood count test results containing an increased number of platelets, red cell and white cells "neutrophils" as well. This pathway is called "Essential or Primary Polycythemia". Platelets count in Essential primary PV can be outside the normal ranges (greater than 500,000) and can reach 1,100,000 or be higher if worsen or left untreated, also these complications can result in strokes.
Why do white blood cells and platelets rise even though the PV is a disease associated to red blood cells only?
The scientific fact tell that: Most of the three cells arise from one origin's cell which then divide into the three types after that, and from this we conclude that if there is a defect in the production of red blood cells, the production of platelets and white blood cells will certainly be affected.
Furthermore, the bone marrow produces two mother cells called "myeloid", "Megakaryocyte" which they are the mother cells for the red cells, platelets, and some white cells, therefore when the responsible genes for guiding cells for the nominated proliferation (JAK2) mutates, a benign tumor occurs in these two mother cells,
therefore, they divide faster to produce an unwanted uncontrolled larger number of red blood cells, platelets, and some types of white cells (WBCs) called (e.g. granulocytes).
That was the typical answer for what happen to platelets during polycythemia type 3 (essential or primary)?
Which occurs first in PV patients, the elevated RBCs or the Elevated platelets?
In medicine and from the 2008 WHO thresholds, doctors may falsely think the early stage PV is essential thrombocythemia (ET) or another condition that may be called myeloproliferative neoplasm unclassifiable (MPN-U) which put the patients on risk of misdiagnosis, therefore the platelets count may become elevated first even to a mild elevation (e.g. 490,000) before the CBC test reveals high RBCs count (Erythrocytosis).
But, High RBCs due to a natural condition (e.g. living on high altitude) might not cause high platelets count at all, because the additional numbers of RBCs are produced to carry more oxygen and enhancing breath, thus the elevated red blood cells count isn't a disease but a natural mechanism to enhance the lungs ability for well breathing in high altitude places.
Do not white blood cells and platelets increase mainly due to the presence of infections, why do white blood cells and platelets count increase in the blood even though polycythemia does not cause infections?
Medically, Polycythemia vera (PV) occurs as a result of chronic inflammations and end with a benign tumor "neoplasm", therefore, causes an abnormal excessive production (myeloproliferation) of red blood cells in the first place, then followed by an increase in white blood cells and platelets as complications of that, therefore, the rise of white blood cells and platelets could be for the both reasons, the chronic inflammation and neoplasm-caused production.
Reminder: What do High Lymph WBC and High PLT mean in my lab results?
Are platelets high in Polycythemia vera?
Yes, platelets level is high in blood count test in many lab results of cases with PV disease which called a Essential thrombocytosis by medical doctors, because the elevated platelet level caused mainly by a defect in platelets manufacturing process not by reactive disease like the other types of thrombocytosis (i.e. reactive thrombocytosis).
Is elevated platelets count in PV a good or bad thing?
It became clear to doctors that if Polycythemia vera develops in the blood, it leads to some undesirable complications, such as an increase in blood platelets level without the need for this extra normal number, so we can assure you that the presence of a high platelet count in your blood count test has not Never a good sign.
Causes of high platelets in Polycythemia vera
The reasons of why PV occur may include:
- JAK2 gene mutation: Some studies believe that a mutation of the JAK2 (Janus kinase 2) gene is the main reason (primary PV) that lead to over production of RBCs and followed by over production of platelets and WBCs.
- Natural elevations: People who suffer from shortness of breath for any reason may develop an over increasing number of red blood cells and platelets, then return to normal levels when breathing is maintained again because the overproduced RBCs and PLTs is due to secondary physiological causes that aren't belong to bone marrow illness or genetics mutation.
- A Heart Disease: such as congenital heart disease (CHD) in adults and Heart failure are of diseases that cause abnormal breath also can elevate RBCs count thus may lead to Polycythemia Vera, next the platelets will increase.
- Erythropoietin, is the hormone stimulate Erythrocytosis (making red blood cells) in the bone marrow tissue, it may increase due to many reasons which induce overproduction of RBCs and PLTs.
That’s also the answer for why are the platelet count and white count elevated in PV?
Can I have polycythemia and normal platelets count?
Frankly, early PV may be misdiagnosed due to many reasons, also some patients with essential thrombocythemia (ET) have an early stage polycythemia, the same occurs with myeloproliferative neoplasm unclassifiable (MPN-U). i.e. you may have high platelets count and no polycythemia or may have polycythemia without high platelets as well.
When to worry about high platelets during polycythemia?
PV disease causes the blood to be thicker than the healthy status which may lead to slower blood flow than usual and possible blood clot formation may occur, therefore if you found high platelets count than normal when you’re suffering from PV disease, it will be better if you seek medical care as soon as possible to avoid undesirable complications. Also most of PV patients will develop a degree of thrombocytosis according to many scientific studies out there and is usually seen in the lab results.
What is platelet count in polycythemia vera?
By tracking the laboratory results of many patients with PV, we usually notice their platelet count is elevated above the normal limit (450,000), i.e. platelets high count may be a number from 450,000-900,000/µL. that means that there is no definite platelets count that's associated with polycythemia vera patients therefore, if you RBCs and PLTs is high in the CBC test, you have PV even the platelets level is mildly elevated.
PV does not cause low platelets count
Mild elevated PLTs or high-normal levels during polycythemia reactivity can be due "homeostasis system" in the human body which resists any change could be occur and reserve the balanced condition in the whole body, thus no change could be happen in platelets due to simple increase in RBCs due to PV
How to Read Your Lab Results?
Firstly, your lab report contain a header to show your personal information such as the name, age, gender, and date you have visited the laboratory. Also, the footer in the below may show the info. about the lab and the manager or technician who performed your test. In the middle, the report contain the findings that result after doing the test (the test result).
The test result consists of right column to show the test name, the left column contains the "reference range" which used by labs to define the normal limits, the middle column shows the results found after testing. Also, some signs and marks can be appear near of the results you can understand their meaning there, understand the lab signs and flags
Treatment of High platelets in PV
If there is no mutation in the genes, Polycythemia will be cured, and the number of red blood cells and platelets, or any other complications will return to the normal picture before the disease occurred. But if PV is genetic, yet there's no definitive cure except the good health care.
Phlebotomy is the treatment of choice for the PV patients, in which a blood amount is drawn to reduce the increased number of blood cells.
Surely, we can't list all causes and information about effect of PV and PLT on each others, hopefully you can understand that, also we can present you professional explanation for your lab results through messages, comments, Fb page and group.
