Table 1.

Study design highlighting the strain, age, sex, number of cages, scoring criteria, cage change criteria, and microenvironmental validation measures for each study

Study	Phase	Age/sex	No. of cages at beginning of study	No. of cages at end of study	Study duration (wk)	Scoring criteria	Cage change criteria	Microenvironmental validation measure
Mixed strains	Learning	Variable, unequal number of males and females	100	98	10	Visual scoring: score of 1, small (diameter 1–2 in.), light-brown urine spots with diffuse boundaries; score of 2, moderate-sized (diameter 2–3 in.), medium-brown urine spots with diffuse boundaries; score of 3, moderate- to large-sized (diameter 3–4 in.), dark-brown urine spots with distinct edges; score of 4, large (diameter 5–6 in.), dark-brown urine spots with distinct edges	Two of 3 observers score 3 or 4	None
Swiss Webster	Learning	Variable, unequal number of males and females	28	28	4		Two of 3 observers score 3 or 4, ammonia level >50 ppm	Ammonia (Draeger X-am 5000 and pump)
C57BL/6J	Learning	Six weeks old, equal numbers of males and females	120	109	7			Ammonia (Draeger X-am 5000 and pump, small animal ammonia sensor), CO2 sensor
C57BL/6J	Validation	Fifteen to 16 wk old, equal numbers of males and females	120	109	8	BSI measured 24/7 by digital caging	AI algorithm based on BSI values determined cage change interval	None
BALB/c	Validation	Six weeks old, equal numbers of males and females	30	28	7			Ammonia (Draeger X-am 5000 and pump), CO2 sensor