SIGNIFICANT ACCOUNTING POLICIES (Tables)

3 Months Ended

Aug. 31, 2022

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	August 31, 2022		May 31, 2022
Raw materials	$	1,732,000	$	1,717,000
Work in progress		723,000		763,000
Finished products		449,000		782,000
Total gross inventory	$	2,904,000	$	3,262,000
Inventory reserves		(982,000)		(846,000)
Net inventory	$	1,922,000	$	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	(15,000)		0.95
Cancelled or expired	(64,000)		4.78
Outstanding August 31, 2022	2,388,616	$	3.69

Disaggregation of Revenue [Table Text Block]

	Three Months Ended August 31,
	2022		2021
Clinical lab	$	1,146,000	$	886,000
Over-the-counter		213,000		79,000
Physician's office		183,000		257,000
Contract manufacturing		95,000		40,000
Total	$	1,637,000	$	1,262,000