ZENITH LABORATORIES INC <ZEN> 4TH QTR LOSS Shr loss 24 cts vs profit 23 cts Net loss 5,106,000 vs profit 5,120,000 Sales 11.4 mln vs 20.4 mln Year Shr loss 19 cts vs profit 73 cts Net loss 4,062,000 vs profit 15.7 mln Sales 50.4 mln vs 80.5 mln Avg shrs 21.7 mln vs 21.6 mln NOTE: 1986 net includes tax credits of 2,742,000 dlrs in quarter and 5,903,000 dlrs in year.