Fisher Diagnostics pulls ammonia calibrator lots after labs report results up to 15% low

Fisher Diagnostics has told customers of its Infinity ammonia calibrators to act after labs reported readings that ran too low, a notice published by the Dutch health inspectorate IGJ shows. The company's own notice is dated 20 October 2026, and the IGJ posting is dated 9 November 2026.

The commercial exposure cannot be sized from the public summary. It gives no figures for affected units, lots or customers, and nothing on replacement, credit or refund terms. Scope is defined by purchase: the action covers customers who bought the products listed in a table in the notice, and that table is not reproduced in the IGJ summary.

The complaints came from laboratories that changed to a new lot of ammonia standards. They measured calibration readings roughly 6% to 15% below expectation and pointed to the calibrators as the cause. Fisher Diagnostics says the error could push patients into the wrong risk category relative to death-risk cut-offs, hold up urgent treatment, and lead to wrong clinical decisions, any of which could seriously harm patients. WMDE B.V. is named as the authorised representative, and the IGJ page links to a four-page English-language PDF.

The summary does not give a root cause or describe the fix, so the full notice is the only reliable source for what customers must do. As general context, makers of medical devices, including diagnostics, must monitor products once they are on the market. They must notify users and the competent authority when a risk emerges.