Meridian

A lab-grade result in a room with no lab.

The client had a proven assay and a working laboratory prototype the size of a filing cabinet. They needed a product a rural clinic could put on a counter, run with a nurse's training, and trust. The target was a five-part differential in under four minutes, at a unit cost that made sense for clinics buying one at a time.

The hard constraints were fluidics that would not clog in a dusty room, a sample path that a non-specialist could clean, and a regulatory submission on a fixed date tied to the next funding round.

Shrank the fluidics first, then designed the box around them.

We spent the first phase in clinics, watching how samples actually move through a shift. That changed the brief: the cartridge had to load one-handed, and the instrument had to tell the user what to do next without a manual. Everything downstream followed from those two findings.

Phase two reduced the fluidic path to a single moulded manifold and a disposable cartridge, which cut the pump count from six to two and took most of the cleaning burden out of the instrument. We proved it with a breadboard that ran two thousand cycles before we drew an enclosure.

The development phase ran in four build rounds. Each round retired named risks from the register: optical alignment drift over temperature, cartridge seating, EMC with the peristaltic drive, and the touch interface under gloved use. Formative usability studies ran alongside every round, so the summative validation at the end confirmed what we already knew.

Design transfer took the instrument to a contract manufacturer in the client's region. We wrote the work instructions, built the end-of-line test fixture, sat through the first pilot build, and handed over a design history file that was complete on the day of design freeze.

• The cartridge door doubles as the optical shutter, so a user cannot start a run with the path open. One part, two functions, one fewer failure mode.
• The manifold is moulded in a medical-grade COC with a laser-welded lid, replacing fourteen tubing joints from the lab prototype.
• A thermally isolated optics bench floats on three flexures. Alignment held through a 5 to 40 degree soak and a 1.2 metre bench drop.
• The interface has eleven screens. The lab prototype had sixty-three.
• Every unit carries an end-of-line calibration record on its own memory, so field service never needs the factory database.

The submission went in on the date set two years earlier. The instrument is in production and the client's own engineering team now owns the design, using the files and procedures we built together.