aPTT
Medical abbreviation · Laboratory Test
| Stands for | Activated partial thromboplastin time |
|---|---|
| Categories | Medical |
aPTT stands for Activated partial thromboplastin time, a laboratory test abbreviation.
The PTT performed with a contact activator such as silica, kaolin or ellagic acid, which shortens and standardizes clotting times to roughly 25 to 35 seconds. It is the traditional monitoring test for unfractionated heparin, with therapeutic targets often around 1.5 to 2.5 times the control value.
Example: Baseline aPTT normal at 29 seconds; heparin bolus given and infusion started.
Usage notes
The lowercase "a" is conventional, though APTT is also seen. Many hospitals now monitor heparin with anti-Xa assays because the aPTT is skewed by acute-phase proteins, high factor VIII levels and lupus anticoagulant. Hemophilia A and B classically prolong the aPTT while leaving the PT normal.
Related abbreviations
More laboratory test abbreviations
- ALT – Alanine aminotransferase
- ANA – Antinuclear antibody
- ANC – Absolute neutrophil count
- anti-CCP – Anti-cyclic citrullinated peptide antibody
- Anti-Xa – Anti-factor Xa assay
- ApoB – Apolipoprotein B
- ASO – Antistreptolysin O
- AST – Aspartate aminotransferase
- BCx – Blood cultures
- BE – Base excess
- BG – Blood glucose
- BMP – Basic metabolic panel
See all 135 laboratory test abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.