SIGNIFICANT ACCOUNTING POLICIES (Tables)

9 Months Ended

Feb. 28, 2023

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	February 28, 2023		May 31, 2022
Raw materials	$	1,714,000	$	1,717,000
Work in progress		924,000		763,000
Finished products		234,000		782,000
Total gross inventory	$	2,872,000	$	3,262,000
Inventory reserves		(808,000)		(846,000)
Total	$	2,064,000	$	2,416,000

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

	Option Shares	Exercise Price Weighted Average
Outstanding May 31, 2022	2,321,616	$	3.72
Granted	146,000		3.37
Exercised	(46,500)		1.73
Cancelled or expired	(107,750)		4.76
Outstanding February 28, 2023	2,313,366	$	3.69

Disaggregation of Revenue [Table Text Block]

	Three Months Ended February 28,				Nine Months Ended February 28,
	2023		2022		2023		2022
Clinical lab	$	532,000	$	731,000	$	2,580,000	$	2,259,000
Over-the-counter		292,000		244,000		971,000		857,000
Contract manufacturing		284,000		167,000		431,000		319,000
Physician's office		4,000		6,518,000		249,000		10,134,000
Total	$	1,112,000	$	7,660,000	$	4,231,000	$	13,569,000