Test Overview
Test Methodology

Chromogenic Substrate Assay

Test Usage

Monitoring Factor 8 replacement therapy in patients with Hemophilia A. This assay will be affected by concomitant emicizumab.

Reference Range *

*Reference ranges may change over time. Please refer to the original patient report when evaluating results.

50 - 150%

Test Details
Days Set Up
Monday through Friday, one run per day
Analytic Time

1 hour

Soft Order Code
Specimen Requirements
Collection Instructions

Collect specimen in blue top (citrate 3.2%) tube. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, and aliquot plasma into a polypropylene plastic vial, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device); the line should be flushed with 5mL of saline and the first 5mL of blood or six dead space volumes of the VAD discarded.

Normal Volume
Full 2.7 mL tube or 1 mL plasma aliquot
Minimum Volume
Full 1.8 mL tube or 1 mL plasma aliquot
Storage Temperature
Room temperature for whole blood or frozen aliquot of citrated plasma.
Rejection Criteria
Specimens will be rejected if not properly filled, clotted, grossly hemolyzed, or contaminated with heparin.
CPT Code
Fee Code
NY State Approved