FDA Lists Class I Recall of Werfen's HemosIL AcuStar HIT Antibody Test

The Food and Drug Administration's medical device recall database now lists a Class 1 recall of the HemosIL AcuStar HIT-IgG(PF4) assay, a laboratory test made by Instrumentation Laboratory (IL) of Bedford, Massachusetts. The recall notice directs customers to local Werfen representatives, and IL's announcements for the test appear on Werfen's website. The manufacturer's stated reason is a "Potential for invalid calibration curve or negative mean bias of up to 47% with patient samples."

The two database entries, numbered Z-0001-2027 and Z-0002-2027, were first posted on October 10, 2026, and were last updated on October 30. Both are marked as open and classified.

What is covered

The assay is used for HIT antibody testing. Werfen lists the test among its HemosIL reagents for heparin-induced thrombocytopenia. The FDA files it under the product classification "Platelet factor 4 radioimmunoassay", product code LCO, and both recall entries reference 510(k) number K170854.

The first entry covers part number 0009800127, lots B40005, with an expiration date of January 16, 2027, and B38062, which expires on November 1, 2026. It lists 434 units in commerce. Distribution covered 15 U.S. states, including California, Florida, Massachusetts, New York and Pennsylvania, and more than 20 other countries, among them Germany, France, the United Kingdom, Japan, South Korea and India.

The second entry covers part number 0009802028, a version of the assay the FDA describes as "in vitro diagnostic (OUS only)", meaning it is sold outside the United States. Its lots are B40006 and B38063, with the same expiration dates.

What laboratories were told

According to the FDA entry, Instrumentation Laboratory notified customers on or about September 3, 2026, by email and mailed recall letter. Customers were told to check inventory for affected lots, destroy any remaining product under their own facility procedures, and record the quantity and date of destruction on a response form.

The entry also states: "Consignees were asked to identify an alternative method for HIT antibody testing as a supply interruption is expected and work local Werfen representatives for guidance and transition support."

On September 29, the company sent an expanded recall notification that added further lot numbers, the entry says. The instructions were unchanged. Laboratories were also asked to tell all laboratory staff, forward the notice to affected departments and return the response form within 10 days, even if they held no remaining product.

Cause still under review

The FDA lists the cause of the problem as "Under Investigation by firm." The agency notes on each entry that recall cause determinations are subject to change until a recall is terminated, and that the open status means not all products have yet been corrected or removed.

The database entries do not describe any reported injuries, and they do not say how many patient results may have been affected. The company's notice and the FDA entries are the only public record of the recall cited here.