Normal range 25-35 seconds. Specimen: Plasma (sodium citrate).
Also known as: PTT, partial thromboplastin time.
25-35 secondsCritical value: read below
Reference range
Conventionalseconds
2535
Combined adult band. LabVals does not publish separate men's, women's, or pediatric ranges for Activated Partial Thromboplastin Time (aPTT); those can be narrower than the band shown.
Activated Partial Thromboplastin Time (aPTT) reference range, specimen, and conversion details
Convert any Activated Partial Thromboplastin Time (aPTT) result between units on the unit converter.
What is the normal range for Activated Partial Thromboplastin Time (aPTT)?
The standard teaching reference range for Activated Partial Thromboplastin Time (aPTT) is 25-35 seconds. This value is measured in plasma (sodium citrate).
What is a critical Activated Partial Thromboplastin Time (aPTT) value?
For Activated Partial Thromboplastin Time (aPTT), the commonly taught critical (panic) value is: > 70 seconds (bleeding risk). Critical results are reported to the provider immediately under your facility's policy.
Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population - always use the range printed on the actual result.
Above the range
What causes a high Activated Partial Thromboplastin Time (aPTT)?
Monitors unfractionated heparin; therapeutic is roughly 1.5-2.5× control.
Keep protamine sulfate available as the heparin antidote.
PremiumDrill the Coagulation Studies deck
You have the Activated Partial Thromboplastin Time (aPTT) range. Premium unlocks the 7-card Coagulation Studies flashcard deck with mastery tracking, study sheets that put several panels on one printable page, and unlimited practice across all 440 quiz questions - the free round stops at 10 a day.