Rare diseases · Sign or symptom
Prolonged partial thromboplastin time
HP:0003645
What it means
Increased time to coagulation in the partial thromboplastin time (PTT) test, a measure of the intrinsic and common coagulation pathways. Phospholipid, and activator, and calcium are mixed into an anticoagulated plasma sample, and the time is measured until a thrombus forms.
Rare diseases that can present with this24
Very common80–99%
8Common30–79%
8Sometimes5–29%
8- Autoerythrocyte sensitization syndrome
- Bleeding disorder in hemophilia A carriers
- Glycogen storage disease due to glycogen branching enzyme deficiency
- Marburg hemorrhagic fever
- Monosomy 13q34 syndrome
- Ornithine transcarbamylase deficiency
- Pancreatic hypoplasia-diabetes-congenital heart disease syndrome
- Von Willebrand disease
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Abnormal partial thromboplastin time · Delayed thromboplastin generation · Partial thromboplastin time prolonged · Prolonged activated partial thromboplastin time · Prolonged PTT
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.