ICD-10 Code D75.839 – Thrombocytosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D75.839 – Thrombocytosis, unspecified
What it is
Thrombocytosis means an abnormally increased platelet count. This unspecified code is used when the record documents thrombocytosis but does not identify the cause or a more specific type.
Clinical signs
Clinical features vary; refer to documentation. Patients may be asymptomatic, and the finding is often identified on a complete blood count. Signs of an underlying disorder, if present, should be documented separately.
When to use this code
Use this code when the provider documents thrombocytosis without further detail. It fits cases where the elevated platelet condition is noted, but no reactive, essential, or secondary cause is specified. If the chart identifies an underlying diagnosis, code that condition as directed.
Do not use for
Do not use this code if the record specifies essential thrombocythemia, secondary thrombocytosis, or another defined platelet disorder. Check documentation when thrombocytosis is only a lab finding tied to a different confirmed diagnosis.
Coding tip
Query for the cause or type of thrombocytosis before defaulting to unspecified.