aPTT Reagent Lot Change at the University Campus core clinical laboratory, Tuesday, April 23, 2024

On Tuesday April 23, 2024, at 10:00 A.M., the University Campus core clinical laboratory will be changing to a new lot of aPTT reagent. This will also impact heparin nomograms as discussed below.

The aPTT reference range will remain the same at 22-31 seconds.

Because of the significant variability in response of aPTT reagents to heparin, a heparin responsiveness study was conducted to establish a new goal aPTT range of 47-63 seconds. This is a reasonable target range to use when treating conditions such as uncomplicated venous thromboembolism.

Adjustments to the Adult Heparin Standard Nomograms, the Adult Heparin High Bleed Risk Nomogram and the Adult Heparin Custom Nomogram will occur to account for the change in the new goal aPTT range. Reentry of the above existing heparin nomograms will be facilitated by pharmacy after modification of the aPTT goal ranges in the heparin nomograms has occurred.

Technical questions concerning this change should be directed to the Hemostasis and Thrombosis Laboratory at 356-3573 or Dr. Anna Merrill (678-8400, anna-merrill@uiowa.edu). Pharmacy questions concerning this change should be directed to Ryan Hobbs (356-2577, ryan-hobbs@uiowa.edu).