Chemistry specimen acceptability: a College of American Pathologists Q-Probes study of 453 laboratories

To determine the frequency and reasons for rejection of chemistry specimens.

College of American Pathologists Q-Probes laboratory quality improvement study prospectively recording rejected chemistry specimens in 453 laboratories.

Percentage of submitted specimens rejected for testing.

Of 10,709,701 chemistry specimens submitted to the participating laboratories during the data collection period, 37,208 (0.35%) were rejected prior to testing. The institutional 10th, 50th (median), and 90th percentiles were 1.35%, 0.31%, and 0.06%, respectively. The most frequent reason for rejection was hemolysis, which occurred five times more frequently than the second most cited reason, insufficient specimen quantity to perform the test. When examined with their respective frequency of use, a higher percentage of rejected specimens were collected in microcollection tubes than in other containers. When compared with the respective frequency with which they collect specimens, laboratory personnel submitted significantly fewer rejected specimens than other in-hospital personnel groups and slightly more than out-of-hospital nonlaboratory personnel. The poorest performance was demonstrated by other in-hospital nonlaboratory personnel. Serum and plasma oxalate/fluoride specimens exhibited significantly lower rejection rates when compared with the other specimen types. Relative rejection rates were higher for nongel tubes and lower for syringes when compared with gel tubes.

Specimen rejection should be monitored on a regular basis. Institution-specific factors that are associated with rejection should be identified and targeted for improvement efforts. Action thresholds should be set sufficiently low to assure that continuous improvement is effected.