h-hydrogen

In the search for more powerful tools for diagnoses of endemic diseases in resource-limited settings, we have been analyzing technologies with potential applicability. Increasingly, the process focuses on readily accessible bodily fluids combined with increasingly powerful multiplex capabilities to unambiguously diagnose a condition without resorting to reliance on a sophisticated reference laboratory. Although these technological advances may well have important implications for the sensitive and specific detection of disease, to date their clinical utility has not been demonstrated, especially in resource-limited settings. Furthermore, many emerging technological developments are in fields of physics or engineering, which are not readily available to or intelligible to clinicians or clinical laboratory scientists.

This review provides a look at technology trends that could have applicability to high-sensitivity multiplexed immunoassays in resource-limited settings. Various technologies are explained and assessed according to potential for reaching relevant limits of cost, sensitivity, and multiplex capability. Frequently, such work is reported in technical journals not normally read by clinical scientists, and the authors make enthusiastic claims for the potential of their technology while ignoring potential pitfalls. Thus it is important to draw attention to technical hurdles that authors may not be publicizing.

Immunochromatographic assays, optical methods including those involving waveguides, electrochemical methods, magnetorestrictive methods, and field-effect transistor methods based on nanotubes, nanowires, and nanoribbons reveal possibilities as next-generation technologies.

Although numerous lateral flow immunoassays (LFIAs) have been developed and widely used, inadequate analytical sensitivity and the lack of multiple protein detection applications have limited their clinical utility. We developed a new LFIA device for the simultaneous detection of high-sensitivity cardiac troponin I (hs-cTnI) and myoglobin (Myo).

We used a gold nanoparticle (AuNP) doubly labeled complex, in which biotinylated single-stranded DNA was used as a linkage to integrate 2 AuNPs and streptavidin-labeled AuNP, as an amplifier to magnify extremely low signals.

The detection limit of 1 ng/L achieved for hs-cTnI was 1000 times lower than that obtained in a conventional LFIA. The detection limit for simultaneously measured Myo was 1 μg/L. The linear measurement ranges for hs-cTnI and Myo were 1–10 000 ng/L and 1–10 000 μg/L, respectively. We observed concordant results between the LFIA and clinical assays in sera from 12 patients with acute myocardial infarction (hs-cTnI r = 0.96; Myo r = 0.98). Assay imprecision was <11% for both hs-TnI and myo.

The described proof-of-principle LFIA method could be used as a point-of-care device in multiple protein quantification and semiquantitative analysis.

Although measurement of whole-blood creatinine at the point of care offers rapid assessment of renal function, agreement of point-of-care (POC) results with central laboratory methods continues to be a concern. We assessed the influence of several potential interferents on POC whole-blood creatinine measurements.

We compared POC creatinine (Nova StatSensor) measurements with plasma enzymatic (Roche Modular) and isotope dilution mass spectrometry (IDMS) assays in 119 hospital inpatients. We assessed assay interference by hematocrit, pH, pO₂, total and direct bilirubin, creatine, prescribed drugs, diagnosis, red blood cell water fraction, and plasma water fraction.

CVs for POC creatinine were 1.5- to 6-fold greater than those for plasma methods, in part due to meter-to-meter variation. Regressioncomparison of POC creatinine to IDMS results gave a standard error (S_y|x) of 0.61 mg/dL (54 μmol/L), whereas regression of plasma enzymatic creatinine to IDMS was S_y|x 0.16 mg/dL (14 μmol/L). By univariate analysis, bilirubin, creatine, drugs, pO₂, pH,plasma water fraction, and hematocrit were not found to contribute to method differences. However, multivariate analysis revealed that IDMS creatinine, red blood cell and plasma water fractions, and hematocrit explained 91.8% of variance in POC creatinine results.

These data suggest that whole-blood POC creatinine measurements should be used with caution. Negative interferences observed with these measurements could erroneously suggest adequate renal function near the decision threshold, particularly if estimated glomerular filtration rate is determined. Disparity between whole-blood and plasma matrices partially explains the discordance between whole-blood and plasma creatinine methods.

Although a theoretical consideration suggests that point-of-care testing (POCT) might be uniquely vulnerable to error, little information is available on the quality error rate associated with POCT. Such information would help inform risk/benefit analyses when one considers the introduction of POCT.

This study included 1 nonacute and 2 acute hospital sites. The 2 acute sites each had a 24-h central laboratory service. POCT was used for a range of tests, including blood gas/electrolytes, urine pregnancy testing, hemoglobin A_1c (Hb A_1c), blood glucose, blood ketones, screening for drugs of abuse, and urine dipstick testing. An established Quality Query reporting system was in place to log and investigate all quality errors associated with POCT. We reviewed reports logged over a 14-month period.

Over the reporting period, 225 Quality Query reports were logged against a total of 407 704 POCT tests. Almost two-thirds of reports were logged by clinical users, and the remainder by laboratory staff. The quality error rate ranged from 0% for blood ketone testing to 0.65% for Hb A_1c testing. Two-thirds of quality errors occurred in the analytical phase of the testing process. These errors were all assessed as having no or minimal adverse impact on patient outcomes; however, the potential adverse impact was graded higher.

The quality error rate for POCT is variable and may be considerably higher than that reported previously for central laboratory testing.

Background: Hemoglobin A_1c (Hb A_1c) point-of-care (POC) instruments are a great extent utilized to take care of rapid-turnaround results in diabetic meticulousness centers. We investigated the conformance of diverse Hb A_1c POC instruments (In2it from Bio-Rad, DCA Vantage from Siemens, Afinion and Nycocard from Axis-Shield, Clover from Infopia, InnovaStar from DiaSys, A1CNow from Bayer, and Quo-Test from Quotient Diagnostics) with predominantly accepted playing criteria for Hb A_1c.

Methods: The CLSI protocols EP-10, EP-5, and EP-9 were applied to analyse imprecision, accuracy, and proclivity. We assessed colour using 3 certified unessential quotation calculation procedures and the no matter what of the 3 specification methods. Assay conformance with the Citizen Glycohemoglobin Standardization Program (NGSP) certification criteria, as suited from analyses with 2 rare reagent lot numbers for each Hb A_1c method, was also evaluated.

Results: Because of unsatisfactory EP-10 results, 2 of the 8 manufacturers incontrovertible not to pursue the valuation. The come to CVs from EP-5 evaluations for the varied instruments with a low and outrageous Hb A_1c value were: In2it 4.9% and 3.3%, DCA Vantage 1.8% and 3.7%, Clover 4.0% and 3.5%, InnovaStar 3.2% and 3.9%, Nycocard 4.8% and 5.2%, and Afinion 2.4% and 1.8%. One the Afinion and the DCA Vantage passed the NGSP criteria with 2 strange reagent lot numbers.

Conclusions: Single the Afinion and the DCA Vantage met the acceptance criteria of having a unqualified CV <3% in the clinically applicable cook-stove. The EP-9 results and the calculations of the NGSP certification showed signal differences in analytical playing liaison weird reagent lot numbers for all Hb A_1c POC instruments.