Journal of Applied Laboratory Medicine最新文献

Background: Chamomile administration may have desirable effects in the perioperative setting. Current practice, however, discourages perioperative chamomile use due to a theoretical increase in bleeding. Therefore, we evaluated if chamomile acutely (within 4 h of ingestion) prolongs coagulation assays.

Methods: Eight healthy volunteers were randomized to receive 2 interventions in a crossover design: (a) single dose of chamomile extract capsule (500 mg) and (b) single dose of chamomile tea (3 g in 150 mL water). Interventions were separated at least 3 days apart from each other. Blood was sampled pre-ingestion, 2 h post-ingestion, and 4 h post-ingestion for each intervention. The primary outcome was the maximal change in prothrombin time (PT) before vs after each intervention. Secondary outcomes included changes in international normalized ratio, activated partial thromboplastin time, thrombin time, reptilase time, and fibrinogen levels.

Results: All 8 subjects completed the study. The average pre-ingestion PT values for tea and capsules were 11.9 (1.1) s and 12.0 (0.9) s, respectively. Tea significantly increased the average maximum PT by 0.7 (0.2) s (P = 0.0078). Extract capsules increased the maximum PT by 0.3 (0.2) s (P = 0.06). Neither PT prolongation met the predefined 10% threshold for clinical significance. No significant changes in secondary outcomes were observed.

Conclusions: Chamomile tea ingestion prolongs PT. However, the clinical significance of this is unclear at this time and warrants further investigation. ClinicalTrials.gov Registration Number: NCT05272475.

Background: The importance of offering on-site cardiac troponin (cTn) testing at pediatric hospitals may be underappreciated. We developed a rapid rule-in process for myocardial injury at a pediatric hospital experiencing delays in off-site high-sensitivity cardiac troponin T (hs-cTnT) testing.

Methods: Collect-to-verify turnaround times (TATs) for off-site testing were reviewed. Pre-analytic changes to improve TATs were devised, implemented and evaluated, after which a new analyzer was selected and evaluated for on-site cTn testing. Performance of the new analyzer's assay was compared to the off-site hs-cTnT assay, and post go-live TATs for on-site testing were assessed.

Results: Median collect-to-verify TAT for short turnaround-time (STAT) priority off-site plasma hs-cTnT testing was 104 min, with 35% of orders having a TAT >120 min. Eliminating serum separator tubes and requiring a separate plasma separator tube did not significantly reduce TATs. A QuidelOrtho Triage® MeterPro whole blood cardiac troponin I (cTnI) assay was implemented to "triage" time-critical and STAT priority specimens collected for off-site hs-cTnT testing. Elevated cTnI (≥0.02 µg/L) had a sensitivity of 91% for clear elevations in hs-cTnT (≥53 ng/L) but a 0% sensitivity for modest elevations (5 to 13 ng/L, 14 to 52 ng/L). An interpretive comment was auto-appended to cTnI results indicating that clinicians should wait for the hs-cTnT result if cTnI was normal. Median collect-to-verify TAT for on-site cTnI testing was <50% the TAT for off-site hs-cTnT testing.

Conclusions: On-site point-of-care whole blood cTn testing can rapidly confirm significant or late-presenting myocardial injury. Combined with simultaneous off-site high-sensitivity cardiac troponin (hs-cTn) testing, this workflow is a viable interim solution for pediatric hospitals without on-site hs-cTn testing.

Background: Hemolysis is a common reason for specimen rejection in the laboratory. Our experience suggested that hemolysis (H) flag limits are too strict for some analytes leading to unnecessary specimen rejections. This study summarizes H flags for commonly rejected analytes on the Beckman Coulter DxC 700 AU analyzer.

Methods: We evaluated analytes with low-limit H flags and high rejection rates. These included: aspartate aminotransferase (AST), alanine aminotransferase (ALT), iron (IRN), potassium (K), direct bilirubin (DBIL), magnesium (Mg), amylase (AMY), sodium (Na), gamma-glutamyltransferase (GGT), phosphorus (PHOS), albumin (ALB), alkaline phosphatase (ALKP), and lactate dehydrogenase (LDH). Five patient plasma pools without hemolysis were made from 50 patient specimens. Neat pools were analyzed to establish baseline analyte concentrations. A hemolysate was created by diluting whole blood with distilled water. Each analyte was tested after spiking each pool with the hemolysate to specific hemoglobin concentrations corresponding to manufacturer's H flags. Percent differences were calculated between baseline pool means and each flag's pool mean. Acceptance limits were based upon the average of the 2019 CLIA and the method precision limits. Calculated percent differences greater than the acceptance limits were considered significant.

Results: Manufacturer-defined hemolysis flags can be updated to greater than 1+ for Na, K, and AST, greater than 3+ for ALKP, and greater than 4+ for AMY and Mg. No changes were noted for the remaining analytes.

Conclusions: The hemolysis criteria set for ALKP, AMY, AST, Mg, K, and Na were updated in the Remisol Advance middleware, which led to a 56% reduction in rejected hemolyzed specimens.

Background: Single-sample (screening) rule-out of acute myocardial infarction (AMI) with troponin requires derivation of a single-test screening threshold. In data sets with small event numbers, the lowest one or two concentrations of myocardial infarction (MI) patients dictate the threshold. This is not optimal. We aimed to demonstrate a process incorporating both real and synthetic data for deriving such thresholds using a novel pre-production high-precision point-of-care assay.

Methods: cTnI concentrations were measured from thawed plasma using the Troponin I Next (TnI-Nx) assay (i-STAT; Abbott) in adults on arrival to the emergency department with symptoms suggestive of AMI. The primary outcome was an AMI or cardiac death within 30 days. We used internal-external validation with synthetic data production based on clinical and demographic data, plus the measured TnI-Nx concentration, to derive and validate decision thresholds for TnI-Nx. The target low-risk threshold was a sensitivity of 99% and a high-risk threshold specificity of >95%.

Results: In total, 1356 patients were included, of whom 191 (14.1%) had the primary outcome. A total of 500 synthetic data sets were constructed. The mean low-risk threshold was determined to be 5 ng/L. This categorized 38% (95% CI, 6%-68%) to low-risk with a sensitivity of 99.0% (95% CI, 98.6%-99.5%) and a negative predictive value of 99.4% (95% CI, 97.6%-99.8%). A similarly derived high-risk threshold of 25 ng/L had a specificity of 95.0% (95% CI, 94.8%-95.1%) and a positive predictive value of 74.8% (95% CI, 71.5%-78.0%).

Conclusions: With the TnI-Nx assay, we successfully demonstrated an approach using synthetic data generation to derive low-risk thresholds for safe and effective screening.

Background: In addition to newborn screening, dried blood spots (DBSs) are used for a wide variety of analytes for clinical, epidemiological, and research purposes. Guidelines on DBS collection, storage, and transport are available, but it is suggested that each laboratory should establish its own acceptance criteria.

Methods: An optical scanning device was developed to assess the quality of DBSs received in the newborn screening laboratory from 11 maternity wards between 2013 and 2018. The algorithm was adjusted to agree with the visual examination consensus of experienced laboratory personnel. Once validated, the algorithm was used to categorize DBS specimens as either proper or improper. Improper DBS specimens were further divided based on 4 types of specimen defects.

Results: In total, 27 301 DBSs were analyzed. Compared with an annual DBS rejection rate of about 1%, automated scanning rejected 26.96% of the specimens as having at least one defect. The most common specimen defect was multi-spotting (ragged DBS, 19.13%). Among maternity wards, improper specimen rates varied greatly between 5.70% and 49.92%.

Conclusions: Improper specimen rates, as well as the dominant type of defect(s), are mainly institution-dependent, with various maternity wards consistently showing specific patterns of both parameters over time. Although validated in agreement with experienced laboratory personnel consensus, automated analysis rejects significantly more specimens. While continuous staff training, specimen quality monitoring, and problem-reporting to maternities is recommended, a thorough quality assessment strategy should also be implemented by every newborn screening laboratory. An important role in this regard may be played by automation in the form of optical scanning devices.

Background: Estimated glomerular filtration rate (eGFR) has become incorporated into multiple clinical management situations. Historically, equations included a Black race coefficient, which lacked biological plausibility and created potential to exacerbate health disparities. A new equation created in 2021 changed the weighting of age, sex, and creatinine by modeling against a diverse cohort and removing the Black race coefficient.

Content: A variety of clinical outcomes including kidney disease risk stratification, medication dosing, patient eligibility for clinical trials, and kidney donation are impacted by implementation of the new equation. Nearly 2 years after its initial publication, many studies have reported on observed analytical performance of the 2021 eGFR determined as diagnostic concordance and percentage of estimates within 30% of measured GFR. Additionally, the potential clinical impacts following adoption of the new eGFR among different patient populations has also been reported. Here we review these studies with a focus on assessing the data associated with the transition from 2009 to 2021 Chronic Kidney Disease Epidemiology Collaboration equations.

Summary: The reported interindividual variation in eGFR performance is significantly larger than any potential benefit derived from race coefficients. Both the 2021 eGFR and the 2009 eGFR analytical performance fall short of the validation cohort performance in most cohorts. However, the 2021 analytical is similar or better than the 2009 eGFR in most cohorts. Implementing the 2021 eGFR will remove a systematic overestimation of kidney function among Black patients.