A simple overlooked blood test result could be silently raising your risk of blood clots.
Imagine your blood slowly thickening over years, platelets accumulating unseen until a sudden heart attack or stroke reveals the truth. For many patients with essential thrombocythemia (ET), this scenario isn't fiction—it's their reality. New research reveals that thrombocytosis (elevated platelet counts) often goes unnoticed for years before ET diagnosis, during which patients face significant risks of devastating thrombotic events1 .
Essential thrombocythemia is a chronic myeloproliferative neoplasm—a type of blood cancer where the bone marrow produces too many platelets5 . These excess platelets, while normal in appearance, often function abnormally, creating a paradoxical situation where patients face increased risks of both blood clots and bleeding6 .
A compelling 2020 study published in the Korean Journal of Hematology uncovered a troubling pattern of delayed diagnosis in ET patients1 . Researchers conducted a retrospective review of medical records from 179 ET patients treated between January 1993 and June 2019.
Identified 32 patients who had undergone complete blood count (CBC) testing before their ET diagnosis1 .
Meticulously reviewed medical records to identify patients with previously documented thrombocytosis1 .
Analyzed circumstances surrounding why thrombocytosis wasn't addressed and tracked changes in blood counts1 .
Documented thrombotic events occurring during the delay period1 .
| Event Type | Number of Patients | Percentage |
|---|---|---|
| Cerebral Infarction | 2 | 33.3% |
| Transient Ischemic Attack | 2 | 33.3% |
| Myocardial Infarction | 1 | 16.7% |
| Thromboangiitis Obliterans | 1 | 16.7% |
| Total | 6 | 100% |
Six patients developed serious thrombotic events during the diagnostic delay period1 .
Thrombotic events represent the most significant cause of morbidity and mortality in ET patients1 3 . The relationship between untreated thrombocytosis and thrombosis is well-established in hematology.
The JAK2 V617F mutation, present in approximately half of ET patients, is particularly associated with increased thrombotic risk3 4 . One study of thrombosis patients found that 29.7% of those with thrombocytosis carried this mutation7 .
| Risk Category | Criteria | Thrombosis Risk |
|---|---|---|
| Very Low | Age ≤60 years, no thrombosis history, JAK2 wild-type |
Lowest risk
|
| Low | Age ≤60 years, no thrombosis history, JAK2 mutation present |
Low risk
|
| Intermediate | Age >60 years, no thrombosis history, JAK2 wild-type |
Moderate risk
|
| High | History of thrombosis or age >60 years with JAK2 mutation |
Highest risk
|
Based on current risk stratification models3
While many ET patients are asymptomatic at diagnosis, various symptoms can suggest the condition8 .
Many of these symptoms are non-specific and can be associated with other conditions. Persistent or concerning symptoms should always be evaluated by a healthcare professional.
| Tool | Function | Importance in ET Diagnosis |
|---|---|---|
| Complete Blood Count (CBC) | Quantifies blood cells, including platelets | Initial detection of thrombocytosis; monitoring |
| Peripheral Blood Smear | Allows visual examination of blood cells | Assess platelet morphology; rule out other disorders |
| JAK2 V617F Mutation Test | Detects specific genetic mutation | Present in ~50% of ET cases; major diagnostic criterion |
| CALR Mutation Test | Identifies calreticulin gene mutations | Detects ~30% of ET cases (JAK2-negative) |
| MPL Mutation Test | Finds mutations in thrombopoietin receptor gene | Identifies small subset of JAK2/CALR-negative cases |
| Bone Marrow Biopsy | Examines blood cell production at source | Shows megakaryocyte proliferation; rules out other disorders |
The findings from the Chungnam National University study highlight several critical opportunities for improving patient outcomes1 :
Since physicians overlooked thrombocytosis in nearly 90% of cases in the study, better education about the significance of persistent thrombocytosis is essential.
Implementing protocols to ensure abnormal blood count results receive appropriate follow-up could significantly reduce diagnostic delays.
Hematologists need to collaborate closely with cardiologists, neurologists, and other specialists who may encounter ET patients initially presenting with thrombotic events.
Helping patients understand the importance of abnormal test results can empower them to participate more actively in their healthcare.
While current treatments effectively manage thrombotic risk for many ET patients using aspirin and cytoreductive agents like hydroxyurea, ongoing research continues to improve our approach3 5 .
The discovery of the JAK2 mutation has opened new avenues for targeted therapies, and clinical trials continue to explore more effective treatments with fewer side effects.
The next time you receive blood test results, pay attention to those platelet numbers—they might be trying to tell you something important. When it comes to essential thrombocythemia, what you don't know can hurt you, but awareness and appropriate action can significantly alter the disease course.