SIGNIFICANT ACCOUNTING POLICIES (Tables)

3 Months Ended

Aug. 31, 2021

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	August 31, 2021		May 31, 2021
Raw materials	$	1,493,000	$	1,583,000
Work in progress		926,000		1,006,000
Finished products		443,000		617,000
Total	$	2,862,000	$	3,206,000

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

	Option Shares	Exercise Price Weighted Average
Outstanding May 31, 2021	2,081,366	$	3.59
Granted	24,000		4.25
Exercised	(1,500)		2.68
Cancelled or expired	(22,750)		3.02
Outstanding August 31, 2021	2,081,116	$	3.60

Disaggregation of Revenue [Table Text Block]

	Three Months Ended
	August 31, 2021		August 31, 2020
Clinical lab	$	886,000	$	582,000
Physician's office		257,000		197,000
Over-the-counter		79,000		185,000
Contract Manufacturing		40,000		180,000
Total	$	1,262,000	$	1,144,000