[The second biennial of the External Quality Evaluation Program in Urinalysis (PEECU)].
OBJECTIVE
To characterize the participation of clinical laboratories in the second biennial of an external quality assurance scheme for urinalysis in Mexico.


METHODS
The participants received 32 control samples in 8 shipments of 4 controls each during the biennial 1999-2000. The controls were in the form of tablets to be dissolved in 12 mL of water to mimic urine. The participants performed dipstick assays of pH, specific gravity (SG) and 8 analytes (proteins, glucose, ketones, blood, bilirubin, nitrites, urobilinogen, leukocytes) in the controls. Expected control values were assigned by 10-15 replicate automated assays using dipsticks and apparatus of a single provider (Bayer). Participants' results were transformed to scores ranging from zero (perfect result) to 400 (worst possible). Score differences were analyzed using nonparametric methods (Kruskal-Wallis and Mann-Whitney).


RESULTS
The best results were seen for nitrites, ketones and proteins (mean global scores = 3-5) and the worst for SG (score = 45) with intermediate scores of 10-13 for the other six.


CONCLUSIONS
The scores improved for the second biennial from a grand mean of 17 in the first significantly down to 12 in the second. The number of participants has been increasing yearly and there has been a decrease of participants who do not report at least 3 out of 4 yearly shipments. We confirmed that automated readings yield better scores than visual readings.
Unidad de Epidemiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán Vasco de Quiroga 15, Tlalpan, 14000 México, D.F. aloria@quetzal.innsz.mx
Alvar
A
Loría
Myrna
M
Mejía
Lucía
L
Granados
Erico
E
Hernández
D001331:Automation; D001663:Bilirubin / Q000652:urine; D006417:Hematuria / Q000652:urine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007659:Ketones / Q000652:urine; D007753:Laboratories / Q000592:standards* / Q000706:statistics & numerical data; D007958:Leukocyte Count; D008800:Mexico; D009573:Nitrites / Q000652:urine; D015588:Observer Variation; D015397:Program Evaluation; D011507:Proteinuria / Q000652:urine; D011785:Quality Assurance, Health Care / Q000458:organization & administration*; D011934:Reagent Strips; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013046:Specific Gravity; D016482:Urinalysis / Q000592:standards*; D014556:Urine / Q000737:chemistry / Q000166:cytology; D014558:Urobilinogen / Q000652:urine
D007659:Ketones; D009573:Nitrites; D011934:Reagent Strips; D014558:Urobilinogen; D001663:Bilirubin