Journal of Applied Laboratory Medicine最新文献

Background: Allowable total error (ATE) is a quality concept that defines acceptable analytical performance for a clinical laboratory assay. ATE will vary in terms of the amount of error permissible not only between assays but also based on the test setting and the assay's clinical use. In the clinical laboratory, ATE limits are routinely applied, for example, when evaluating new analytical methodology or equipment for patient testing, troubleshooting unacceptable quality control, or in evaluating instrument comparability.

Content: Currently, there are no universally applicable standards for defining the maximum magnitude of allowable error. However, there are several resources available for users to consider when setting ATE limits. Examples include clinical outcomes studies, biological variation of the measurand, state-of-the-art, professional organizations, and requirements set by regulatory agencies and proficiency testing/external quality assessment scheme organizers. Each of these approaches varies in terms of the resulting magnitude of allowable error for the same assay. This review describes these resources in more detail and discusses the strengths and weaknesses of each approach.

Summary: ATE users should be aware of different resources and their limitations before defining acceptance criteria for an assay in their clinical laboratory.

Background: Urine sediment analysis is a cornerstone of diagnostic testing. This study evaluates FUS-3000 Plus, an automated urine sediment analyzer using advanced imaging and artificial intelligence, to assess its technical performance and diagnostic accuracy for routine clinical use.

Methods: The study analyzed 98 urine samples for chemical parameters (pH, protein, blood, leukocyte esterase, and nitrite) and 76 samples for particle analysis (red blood cells [RBCs], white blood cells, epithelial cells, crystals, bacteria) by both FUS-3000 Plus and sediMAX™, the current laboratory analyzer in use. Additionally, 139 samples were tested for glucosuria and proteinuria, with results compared to the Cobas C702. Carry-over, precision, and linearity were assessed by internal quality controls in accordance with Clinical and Laboratory Standards Institute protocols. Accuracy was further evaluated using external quality controls.

Results: FUS-3000 Plus demonstrated strong agreement with sediMAX for nitrites, protein, and leukocyte esterase (kappa values >0.5) and correlated well with the Cobas C702 for glucosuria and proteinuria. However, discrepancies were observed in glucosuria detection, with some samples yielding inaccurate results even during external quality control assessments. A carry-over effect for RBCs required a rinse step after highly concentrated samples.Precision was acceptable (CV: 3%-11%), and Bland-Altman plots showed strong agreement for formed elements (correlation >0.95). However, the analyzer had reduced accuracy in bacteriuria detection.

Conclusion: FUS-3000 Plus is a reliable tool for routine urinalysis, excelling in particle classification. However, improvements are needed in bacteriuria detection and minimizing carry-over effects. Future research should explore its ability to identify additional cellular elements and its diagnostic utility in diverse clinical populations.

Background: The complete blood count (CBC) is widely used across nearly all areas of medicine. While standard CBC markers reflect basic summaries of the blood cells, modern hematology analyzers generate many additional markers from the underlying data distributions-collectively referred to as cell population data (CPD). While CPD markers have been studied in targeted clinical settings, their value for general prognostic tasks has not yet been established. In this brief report, we assess whether CPD markers can provide additional prognostic information beyond CBC markers in general patient cohorts.

Methods: We retrospectively analyzed CBC and CPD markers from over 10 000 patients at a large academic medical center between March 14, 2024, and October 23, 2024. Marker associations with general outcomes (inpatient admission from the emergency department, mortality, and length-of-stay) were analyzed in both univariate and multivariate models. Outcomes were also predicted using CBC- and CPD-based machine learning models.

Results: Many CPD markers were strongly associated with patient mortality, length-of-stay, and inpatient admission from the emergency department. CPD markers showed consistent outcome associations after stratification by patient demographics and medical specialties, and many retained statistical significance after controlling for commonly used CBC markers. In machine learning modelling, inclusion of CPD markers enhanced predictive performance for mortality [area under the curve (AUC): 0.79] and inpatient admission (AUC: 0.81). Analysis of CPD markers revealed 2 phenotypes: an inflammatory phenotype associated with inpatient admission and a dysregulatory phenotype associated with mortality.

Conclusions: These results highlight how routinely collected CPD markers may enhance the use of the CBC for evaluation of general patient cohorts.

Background: Loperamide is a µ-opioid receptor agonist that reduces intestinal peristalsis and is used to treat diarrhea. We previously described significant cross-reactivity of loperamide with 2 fentanyl immunoassays. Since then, new fentanyl immunoassays, including a CLIA-waived point-of-care device, have been approved for clinical use.

Methods: We evaluated new fentanyl immunoassays for cross-reactivity to loperamide and its major metabolites, N-desmethyl loperamide (dLop) and N-didesmethyl loperamide (ddLop). Previously characterized assays were tested for cross-reactivity to ddLop, which recently became commercially available. Loperamide, dLop, and ddLop were spiked in drug-free urine for analysis by 5 enzyme immunoassays run on automated chemistry analyzers and one lateral flow assay for the detection of fentanyl.

Results: Loperamide and its metabolites produced positive results in 3 fentanyl immunoassays. The Immunalysis HEIA was previously determined to be reactive to both loperamide and dLop, but it was not reactive to ddLop. The Immunalysis SEFRIA was reactive to loperamide, dLop, and ddLop at minimum concentrations of 14.7 mg/L, 13.1 mg/L, and 17.0 mg/L. The Thermo Fisher DRI was previously determined to be reactive to loperamide and dLop, and it was reactive to ddLop at a minimum concentration of 33.1 mg/L. The Abbott iCassette, ARK Fentanyl II, and Lin-Zhi LZI II fentanyl assays showed no cross-reactivity to loperamide or its metabolites.

Conclusions: The cross-reactivity of loperamide, dLop, and ddLop in several fentanyl immunoassays has the potential to cause false-positive results during urine drug screening.

Background: Testing for sexually transmitted infections (STIs) in preadolescent patients carries significant medical and legal implications. Guidelines from the Centers for Disease Control and Prevention (CDC) support the use of nucleic acid amplification testing (NAAT) for diagnosis of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) in children. These guidelines also recommend confirmation of positive results by repeat testing of either the original specimen or a separately collected specimen to reduce the risk of false positives. Currently, no FDA-cleared NAATs have a specific indication for use in samples from prepubertal children or for the evaluation of suspected sexual assault. Further, if confirmation using a second assay is desired, manufacturer-specific collection kits may preclude this, necessitating a second specimen collection, which may not be feasible.

Methods: Here, we evaluate the compatibility between the Cepheid Xpert CT/NG assay and the Roche cobas CT/NG assay on samples collected in cobas PCR media.

Results: Our data suggest that the Xpert CT/NG assay is compatible with specimens collected in cobas collection medium.

Conclusions: As such, laboratories may validate this work flow as a confirmatory test on specimens collected in cobas collection medium.

Background: Thromboelastography (TEG) is a viscoelastic testing platform that monitors real-time coagulation. This study evaluated changes in blood use and waste following TEG implementation, as well as changes in massive transfusion protocol (MTP) blood utilization and returns following TEG implementation.

Methods: The study is a retrospective analysis of blood component transfusion in 3 services (cardiothoracic surgery, emergency department, and trauma surgery) and overall blood waste at a level II trauma center for 104 weeks before and after TEG implementation. Blood utilization and waste were compared by a paired t-test. Additionally, MTP blood utilization and returns were compared for 80 cases pre-TEG and 80 cases post-TEG implementation by an independent t-test.

Results: Changes in weekly mean utilization after implementation of TEG differed among component types. Red blood cell (RBC) transfusions increased by 15% (P < 0.01), while plasma transfusions decreased by 26% (P < 0.05). The mean RBC units wasted decreased (P < 0.01), but the mean plasma units wasted increased significantly between the pre- and post-TEG groups (P < 0.001). The weekly mean platelet and cryoprecipitate waste and utilization showed no significant difference between the pre- and post-TEG groups. MTP utilization and returns showed no significant difference between pre- and post-TEG implementation.

Conclusions: In line with previous literature, plasma utilization decreased post-TEG implementation. Plasma waste unexpectedly increased, which may be due to an increase of orders for plasma that were not transfused. RBC utilization and waste showed significant changes, although the impact of blood availability during the COVID pandemic should be considered a confounding variable in this study.