SIGNIFICANT ACCOUNTING POLICIES (Tables)

6 Months Ended

Nov. 30, 2022

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	November 30, 2022		May 31, 2022
Raw materials	$	1,685,000	$	1,717,000
Work in progress		811,000		763,000
Finished products		339,000		782,000
Total gross inventory	$	2,835,000	$	3,262,000
Inventory reserves		(774,000)		(846,000)
Net inventory	$	2,061,000	$	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	(82,500)		5.07
Outstanding November 30, 2022	2,338,616	$	3.69

Disaggregation of Revenue [Table Text Block]

	Three Months Ended November 30,				Six Months Ended November 30,
	2022		2021		2022		2021
Clinical lab	$	902,000	$	642,000	$	2,048,000	$	1,528,000
Over-the-counter		466,000		534,000		679,000		613,000
Physician's office		62,000		3,359,000		245,000		3,616,000
Contract manufacturing		52,000		112,000		147,000		152,000
Total	$	1,482,000	$	4,647,000	$	3,119,000	$	5,909,000