From the Journals

Novel chromogenic assay looks accurate in hemophilia A diagnosis



A novel automated chromogenic assay demonstrated diagnostic accuracy and limited variation in patients with hemophilia A, according to recent study findings.

“The original one‐stage clotting assay is still the most widely used method for measuring FVIII activity in these patients, although the chromogenic assay is recognized to be less prone to the variability related to the use of different reagents and to the presence of interferences,” Cristina Novembrino, MD, of the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, in Milan, and colleagues wrote in Haemophilia. “The choice of the proper assay is a crucial point in the frame of diagnosis, particularly in moderate or mild [hemophilia A] patients.”

The BIOPHEN FVIII:C assay, used on the Sysmex CS‐2400 analyzer, is a novel chromogenic diagnostic tool used to analyze FVIII clotting activity in patients with hemophilia A of all severity levels. The researchers evaluated the diagnostic and clinical capabilities of the assay in 60 patients with hemophilia A and 120 healthy controls.

Dr. Novembrino and colleagues used samples of FVIII deficient plasma and Actin FS to compare the novel tool to a one-stage assay and another chromogenic assay.

After analysis, the researchers found that the inter‐assay and intra‐assay coefficient of variation were less than 6%. The mean recovery and limit of detection were 91.7% (range, 79.8%-98.6%) and 0.2%, respectively.

The linearity test revealed positive results of up to 1/128 dilution (r = 0.99).

“The K coefficient was 0.91 when BIOPHEN FVIII:C was compared with the historical classification of the patients, demonstrating an optimal diagnostic accuracy in hemophilia A,” the researchers wrote.

The novel assay may be an appropriate laboratory tool for the diagnosis and therapeutic monitoring of patients with hemophilia A, they added.

Sysmex Corporation and Hyphen BioMed provided the instrument and reagents for the study. One of the authors is an employee of Sysmex Corporation. The authors reported having no other conflicts of interest.

SOURCE: Novembrino C et al. Haemophilia. 2019 May 2. doi: 10.1111/hae.13746.

Next Article: