Centrifuge not spinning true? Why RPM verification matters

A centrifuge looks like it's doing its job as long as it spins. But the set speed and the actual speed can quietly drift apart — and when they do, your results pay the price. Here's why RPM verification matters more than most labs realize, and how it works.

Why a few hundred RPM matters

Centrifugal force depends on speed. A rotor running below (or above) its set RPM changes the g-force applied to your samples, which can affect packed-cell volumes, density separations, plasma/serum quality, and molecular preps. The result isn't a dramatic failure — it's a subtle, systematic error that's hard to catch because everything looks normal.

How RPM verification works

A technician measures actual rotor speed with a calibrated, NIST-traceable tachometer and compares it to the set speed across the operating range, then verifies the timer. The as-found and as-left readings are recorded against your defined tolerance — commonly around ±5%, depending on application and manufacturer spec.

A centrifuge that's off-speed doesn't break — it just quietly biases every spin.

Keeping it documented

Beyond result quality, CLIA-regulated labs are expected to verify centrifuge performance on a schedule, with documentation. Annual verification with a traceable certificate covers both the science and the survey. Learn more about centrifuge calibration & RPM verification, or request a readiness check to see which of your instruments are due.