Urine Test Strips: How reproducible are readings?

In an experiment, multiple reagent test strips from 90 urine samples were examined twice: observed visually by one of two persons and analyzed by spectrophotometry. Interobserver and intra-observer agreement were calculated and expressed as Cohen's K. Interobserver and intra-observer agreement were moderate to good, but lower than one might expect. Enhancing discoloration of the test pads could improve reproducibility.