Evaluation of Preanalytical Point-of-Care Testing Errors and Their Impact on Productivity in the Emergency Department in the United States.

BACKGROUND: Preanalytical errors due to poor sample quality or improper sample handling may occur with point-of-care testing (POCT). METHODS: A retrospective analysis was conducted using deidentified records for 15 479 i-STAT® cartridges run at the Oregon Health & Science University Emergency Department (ED) between December 2015 and August 2016. Data were collected from electronic health records and device middleware for CG4+, CHEM8+, and Troponin cartridges. The frequency of POCT errors was evaluated by cartridge type. The effect of user experience on error frequency, impact of error on hospital length of stay (LOS), and test turnaround time (TAT) were all evaluated. Direct costs incurred due to Chem8+ and Troponin cartridge waste and indirect costs as avoidable nursing staff labor were estimated over 2 years. RESULTS: A total of 935 erroneous results were identified (6.0% of all cartridges). Three hundred seventy-two (2.4%) were unusable results, and 563 (3.6%) were cartridge errors, of which 163 were classified by device error codes as poor sample quality/improper sample handling. Error rates were inversely correlated with user experience based on number of tests performed during the 9-month period. Compared to nonerroneous results, test TATs and LOS were significantly longer with erroneous results (P < 0.01). Over 2 years, direct costs incurred due to cartridge waste was $45 000, and indirect cost was estimated between 486 and 729 h in avoidable nursing labor. CONCLUSIONS: Preanalytical POCT errors were inversely correlated with user experience and significantly impacted clinical productivity in the ED based on LOS and test TAT.

A Multicenter Evaluation of a Nongel Mechanical Separator Plasma Blood Collection Tube for Testing of Selected Therapeutic Drugs.

BACKGROUND: Some therapeutic drugs are unstable during sample storage in gel tubes. BD Vacutainer® Barricor™ Plasma Blood Collection Tube with nongel separator was compared with plasma gel tubes, BD Vacutainer PST™, PST II, and BD Vacutainer Serum Tube for acetaminophen, salicylate, digoxin, carbamazepine, phenytoin, valproic acid, and vancomycin during sample storage for up to 7 days. METHODS: Seven hospital sites enrolled 705 participants who were taking at least one selected drug. The study tubes were collected and tested at initial time (0 h), after 48 h of storage at room temperature and on day 7 (after additional 5 days of refrigerated storage). The performance of BD Barricor tube was evaluated for each drug by comparing BD Barricor samples with samples from the other tubes at 0 h from the same participant; stability was evaluated by comparing test results from the same tube at 0 h, 48 h, and 7 days. RESULTS: At 0 h, BD Barricor showed clinically equivalent results for selected therapeutic drugs compared with the other tubes, except phenytoin in BD PST. Phenytoin samples ≥20 µg/mL in BD PST had 10-12% lower values than samples in BD Barricor. During sample storage, all selected drugs remained stable for 7 days in BD Barricor and in serum aliquots. In BD PST, all drugs remained stable except phenytoin and carbamazepine and in BD PST II except for phenytoin. CONCLUSION: The BD Barricor Tube is effective for the collection and storage of plasma blood samples for therapeutic drug monitoring without sample aliquoting.

Thermodynamic contributions of single internal rA·dA, rC·dC, rG·dG and rU·dT mismatches in RNA/DNA duplexes.

The thermodynamic contributions of rA·dA, rC·dC, rG·dG and rU·dT single internal mismatches were measured for 54 RNA/DNA duplexes in a 1 M NaCl buffer using UV absorbance thermal denaturation. Thermodynamic parameters were obtained by fitting absorbance versus temperature profiles using the curve-fitting program Meltwin. The weighted average thermodynamic data were fit using singular value decomposition to determine the eight non-unique nearest-neighbor parameters for each internal mismatch. The new parameters predict the ΔG°(37), ΔH° and melting temperature (T(m)) of duplexes containing these single mismatches within an average of 0.33 kcal/mol, 4.5 kcal/mol and 1.4°C, respectively. The general trend in decreasing stability for the single internal mismatches is rG·dG > rU·dT > rA·dA > rC·dC. The stability trend for the base pairs 5' of the single internal mismatch is rG·dC > rC·dG > rA·dT > rU·dA. The stability trend for the base pairs 3' of the single internal mismatch is rC·dG > rG·dC >> rA·dT > rU·dA. These nearest-neighbor values are now a part of a complete set of single internal mismatch thermodynamic parameters for RNA/DNA duplexes that are incorporated into the nucleic acid assay development software programs Visual oligonucleotide modeling platform (OMP) and ThermoBLAST.

Evaluation of effect of specimen-handling parameters for plasma preparation tubes on viral load measurements obtained by using the Abbott RealTime HIV-1 load assay.

HIV-1 viral load testing is essential to the management of HIV-1-infected patients, and proper specimen handling ensures accurate viral load (VL) results. This study was performed to (i) evaluate the effect of freezing plasma in situ in BD Vacutainer plasma preparation tubes (PPT) on the accuracy of HIV-1 viral load results using the Abbott RealTime HIV-1 assay and (ii) evaluate the effect of whole-blood storage in the PPT for 6 h at room temperature prior to centrifugation (PPT6H) rather than 2 h as specified in the PPT product insert. Of the 64 HIV-positive subjects evaluated, 29 had average viral load counts of >40 copies/ml in at least one of the tubes tested and 35 subjects had a result of either "undetected target" or "below the limit of quantification" (LOQ) for all or some of the tubes regardless of handling condition. For the 29 subjects with VLs that were >LOQ, the mean biases between plasma from Vacutainer K(2)EDTA tubes and plasma frozen in situ in PPT and between K(2)EDTA tube plasma and plasma from PPT6H (log(10) copies/ml) were 0.005 and -0.001, respectively, and r(2) was >0.92 for all correlations. We conclude that VLs determined from plasma frozen in situ in PPT are equivalent to VLs in K(2)EDTA tube plasma and can be used for accurate quantification of HIV-1 RNA in the Abbott RealTime HIV-1 assay. Furthermore specimens collected in PPT can be stored for 6 h at room temperature with no effect on viral load results as measured by the Abbott RealTime HIV-1 assay.