Proficiency testing performance in US laboratories: results reported to the Centers for Medicare & Medicaid Services, 1994 through 2006.

CONTEXT: Beginning in 1994, clinical laboratories performing nonwaived testing were required, under the regulations implementing the Clinical Laboratory Improvement Amendments of 1988 (CLIA), to enroll and participate in a proficiency testing (PT) program approved by the Centers for Medicare & Medicaid Services. Successful PT performance is a requirement for maintaining CLIA certification to perform testing in certain specialties and subspecialties and for specific analytes. OBJECTIVE: To evaluate the PT performance from 1994 through 2006 of hospital and independent laboratories (HI) compared with all other testing sites (AOT) for selected commonly performed tests and analytes. DESIGN: Proficiency testing data, from 1994 through 2006, were electronically reported to the Centers for Medicare & Medicaid Services by approved PT programs as required by CLIA regulations. Approximately 16 million PT event scores from 36 000 unique testing sites were sorted into 2 groups based on the type of testing facility: HI or AOT. RESULTS: The PT performance scores for 15 of the most commonly performed tests demonstrated a decline in failure rates for both HI and AOT laboratory groups during 1994 through 2006 (analyte/test values reported in this article include alanine aminotransferase, amylase, bilirubin, cholesterol, digoxin, glucose, hemoglobin, leukocyte count, potassium, prothrombin time, theophylline, thyroxine, triglycerides, white blood cell differential, and uric acid). For most analytes, the difference in failure rates between HI and AOT was statistically significant. The AOT group started with higher failure rates, and remained higher for all analytes, during most years when compared with the HI group; although, over time, that difference diminished. The AOT group showed a greater decline in PT failure than the HI group. For all analytes, the AOT group performance improved during this period. CONCLUSIONS: The PT performance improved dramatically for the AOT group from 1994 through 2006 as measured by a decrease in the percentage of laboratories with unsatisfactory performance for 15 selected analytes. The PT performance in the HI group improved modestly for some analytes during this same period, whereas, for other analytes, the group showed no apparent improvement.

Results of a survey of hospital coagulation laboratories in the United States, 2001.

CONTEXT: Coagulation and bleeding problems are associated with substantial morbidity and mortality, and inappropriate testing practices may lead to bleeding or thrombotic complications. OBJECTIVE: To evaluate practices reported by hospital coagulation laboratories in the United States and to determine if the number of beds in a hospital was associated with different practices. DESIGN: From a sampling frame of institutions listed in the 1999 directory of the American Hospital Association, stratified into hospitals with 200 or more beds ("large hospitals") and those with fewer than 200 beds ("small hospitals"), we randomly selected 425 large hospitals (sampling rate, 25.6%) and 375 small hospitals (sampling rate, 8.8%) and sent a survey to them between June and October 2001. Of these, 321 large hospitals (75.5%) and 311 small hospitals (82.9%) responded. RESULTS: An estimated 97.1% of respondents reported performing some coagulation laboratory tests. Of these, 71.6% reported using 3.2% sodium citrate as the specimen anticoagulant to determine prothrombin time (81.3% of large vs 67.7% of small hospitals, P < .001). Of the same respondents, 45.3% reported selecting thromboplastins insensitive to heparin in the therapeutic range when measuring prothrombin time (59.4% of large vs 39.8% of small hospitals, P < .001), and 58.8% reported having a therapeutic range for heparin (72.9% of large vs 53.2% of small hospitals, P < .001). An estimated 96.3% of respondents assayed specimens for activated partial thromboplastin time within 4 hours after phlebotomy, and 89.4% of respondents centrifuged specimens within 1 hour of collection. An estimated 12.1% reported monitoring low-molecular-weight heparin therapy, and to do so, 79% used an assay for activated partial thromboplastin time (58% of large vs 96% of small hospitals, P = .001), whereas 38% used an antifactor Xa assay (65% of large vs 18% of small hospitals, P = .001). CONCLUSIONS: Substantial variability in certain laboratory practices was evident. Where significant differences existed between the hospital groups, usually large hospitals adhered to accepted practice guidelines to a greater extent. Some reported practices are not consistent with current recommendations, showing a need to understand the reasons for noncompliance so that better adherence to accepted standards of laboratory practice can be promoted.

Assessment of laboratory performance of nucleic acid amplification tests for detection of Mycobacterium tuberculosis.

During implementation of the Centers for Disease Control and Prevention's Mycobacterium tuberculosis nucleic acid amplification (NAA) evaluation program, 27.1% of participants used the same biological safety cabinet for NAA and specimen processing; 28.8% reported not using unidirectional workflow. An association between false positives and adverse responses to quality assurance questions (P = 0.04) illustrated the need for following NCCLS recommendations.