What is the normal range for PTT?

The normal range for activated partial thromboplastin time (PTT) typically falls between 25 and 35 seconds when tested in a laboratory setting, although values can vary slightly based on the specific assays and local lab standards. When considering the options presented, if B is indicated as 60-90 seconds, it's important to note that this range may apply to patients who are on anticoagulation therapy, notably with medications like heparin, rather than representing the normal physiological range.

In a clinical context, a normal PTT indicates that the intrinsic and common pathways of coagulation are functioning adequately without any significant coagulopathy or therapeutic intervention affecting the clotting factors. This measure is essential when evaluating a patient's hemostatic function, particularly prior to surgical procedures or when assessing for bleeding disorders. Therefore, while the value noted in option B is indicative of therapeutic ranges necessary for anticoagulation management, it does not accurately describe the normal PTT range for healthy individuals. Consideration of these therapeutic levels is crucial when interpreting PTT results in a clinical setting.