Miles Labs' Frees made urine testing a dip-and-read strip

Through the 1940s and early 1950s, testing a patient's urine for glucose meant a small wet-chemistry procedure: mix urine with reagent tablets in a test tube, watch for a color change. Miles Laboratories' own Clinitest tablets, introduced in 1941, were a real improvement on the older Benedict's reagent test (no Bunsen burner needed), but running the test still meant a test tube, a dropper to measure the urine sample, and washing the glassware afterward before the next patient — real friction for a test doctors wanted to run routinely.

Alfred and Helen Free, a husband-and-wife biochemist team at Miles's Ames Division, spent years making the tablet-and-tube test itself better: more sensitive, and, with a second reagent called Acetest, able to detect ketones as well as glucose. The improvements all stayed within the same basic apparatus — reagent in solid form, urine measured out with a dropper into a test tube, color read by eye. Nobody working on the problem had questioned whether the tube and dropper were actually necessary at all.

Embedded reagent chemistry onto filter paper so a strip dipped into urine replaced the dropper and tube; a two-enzyme reaction kept it glucose-specific.

Embedding reagent on a strip eliminated the need to measure urine volume, since dipping and removing triggers the reaction.

No test tube meant no glassware to wash between patients, removing a major friction point for routine testing.

The enzyme reaction specific to glucose kept accuracy high, so the simpler format could replace rather than just supplement tube tests.

A portable strip let the test move from hospital labs to doctor's offices and homes, expanding where testing could happen.

When a process needs a vessel, precise dose, and cleanup, ask if the active ingredient can be embedded on a disposable substrate the sample touches directly.

Dip-and-read testing eliminated the test tube, the dropper, the glassware washing and the need for any measuring at all — a doctor, nurse or eventually a patient at home could get a reading from a single strip with no laboratory apparatus whatsoever. Miles extended the same dip-strip principle to protein (Albustix, 1957), then combined multiple reagents onto one strip (Uristix, 1957), eventually reaching a ten-test strip, Multistix 10 SG, by 1981.