Year | Number of participants | Specimens | Correct results for MSU/ CPPD (%) | False positive for MSU/ CPPD (%) | False negative (%) | Labs with no errors (%) | Mean number of errors |
---|---|---|---|---|---|---|---|
1989 | 25 | MSU abundant | 100 | NA | 0 | 80 | 0.32 |
Cholesterol | 80 | 20 | |||||
Triamcinolene hexacetonide | 88 | 12 | |||||
Glove powder | 100 | 0 | |||||
1990 | 36 | MSU abundant | 86 | NA | 14 | 17 | 1.0 |
MSU moderate | 53 | NA | 47 | ||||
MSU rare | 33 | NA | 67 | ||||
1991 | 47 | MSU moderate, extracellular | 70 | NA | 30 | 25 | 1.1 |
MSU moderate, intracellular | 60 | NA | 40 | ||||
Cholesterol | 63 | 37 | |||||
1992 | 35 | MSU moderate | 89 | 5 | 5 | 43 | 0.57 |
MSU rare | 67 | 3 | 31 | ||||
CPPD abundant | 63 | 3 | 34 | ||||
1993 | 40 | MSU moderate | 76 | 17 | 7 | 38 | 1.0 |
MSU rare | 76 | 7 | 17 | ||||
Betamethasone acetate | 53 | 47 | |||||
1994 | 45 | MSU moderate | 94 | 6 | 0 | 38 | 0.44 |
MSU rare | 84 | 8 | 8 | ||||
Sodium oxalate | 66 | 34 | |||||
1995 | 41 | MSU abundant, intracellular chrystal fragments | 57 | 5 | 38 | 39 | 0.61 |
MSU moderate | 89 | 3 | 11 | ||||
MSU rare | 89 | 5 | 5 | ||||
1996 | 47 | MSU moderate | 54 | 4 | 40 | 13 | 1.6 |
MSU rare | 26 | 7 | 67 | ||||
MSU abundant, triamcinolone hexacetonide abundant | 64 | 30 | 7 |
MSU = monosodium urate, CPPD = calcium pyrophosphate dihydrate, NA = not applicable: the CPPD alternative was not included in 1989–1991.