Diagnostic Tests to Support Late-Stage Control Programs for Schistosomiasis and Soil-Transmitted Helminthiases.

Global efforts to address schistosomiasis and soil-transmitted helminthiases (STH) include deworming programs for school-aged children that are made possible by large-scale drug donations. Decisions on these mass drug administration (MDA) programs currently rely on microscopic examination of clinical specimens to determine the presence of parasite eggs. However, microscopy-based methods are not sensitive to the low-intensity infections that characterize populations that have undergone MDA. Thus, there has been increasing recognition within the schistosomiasis and STH communities of the need for improved diagnostic tools to support late-stage control program decisions, such as when to stop or reduce MDA. Failure to adequately address the need for new diagnostics could jeopardize achievement of the 2020 London Declaration goals. In this report, we assess diagnostic needs and landscape potential solutions and determine appropriate strategies to improve diagnostic testing to support control and elimination programs. Based upon literature reviews and previous input from experts in the schistosomiasis and STH communities, we prioritized two diagnostic use cases for further exploration: to inform MDA-stopping decisions and post-MDA surveillance. To this end, PATH has refined target product profiles (TPPs) for schistosomiasis and STH diagnostics that are applicable to these use cases. We evaluated the limitations of current diagnostic methods with regards to these use cases and identified candidate biomarkers and diagnostics with potential application as new tools. Based on this analysis, there is a need to develop antigen-detecting rapid diagnostic tests (RDTs) with simplified, field-deployable sample preparation for schistosomiasis. Additionally, there is a need for diagnostic tests that are more sensitive than the current methods for STH, which may include either a field-deployable molecular test or a simple, low-cost, rapid antigen-detecting test.

A Meta-Analysis of Typhoid Diagnostic Accuracy Studies: A Recommendation to Adopt a Standardized Composite Reference.

Novel typhoid diagnostics currently under development have the potential to improve clinical care, surveillance, and the disease burden estimates that support vaccine introduction. Blood culture is most often used as the reference method to evaluate the accuracy of new typhoid tests; however, it is recognized to be an imperfect gold standard. If no single gold standard test exists, use of a composite reference standard (CRS) can improve estimation of diagnostic accuracy. Numerous studies have used a CRS to evaluate new typhoid diagnostics; however, there is no consensus on an appropriate CRS. In order to evaluate existing tests for use as a reference test or inclusion in a CRS, we performed a systematic review of the typhoid literature to include all index/reference test combinations observed. We described the landscape of comparisons performed, showed results of a meta-analysis on the accuracy of the more common combinations, and evaluated sources of variability based on study quality. This wide-ranging meta-analysis suggests that no single test has sufficiently good performance but some existing diagnostics may be useful as part of a CRS. Additionally, based on findings from the meta-analysis and a constructed numerical example demonstrating the use of CRS, we proposed necessary criteria and potential components of a typhoid CRS to guide future recommendations. Agreement and adoption by all investigators of a standardized CRS is requisite, and would improve comparison of new diagnostics across independent studies, leading to the identification of a better reference test and improved confidence in prevalence estimates.

Electricity-free amplification and detection for molecular point-of-care diagnosis of HIV-1.

In resource-limited settings, the lack of decentralized molecular diagnostic testing and sparse access to centralized medical facilities can present a critical barrier to timely diagnosis, treatment, and subsequent control and elimination of infectious diseases. Isothermal nucleic acid amplification methods, including reverse transcription loop-mediated isothermal amplification (RT-LAMP), are well-suited for decentralized point-of-care molecular testing in minimal infrastructure laboratories since they significantly reduce the complexity of equipment and power requirements. Despite reduced complexity, however, there is still a need for a constant heat source to enable isothermal nucleic acid amplification. This requirement poses significant challenges for laboratories in developing countries where electricity is often unreliable or unavailable. To address this need, we previously developed a low-cost, electricity-free heater using an exothermic reaction thermally coupled with a phase change material. This heater achieved acceptable performance, but exhibited considerable variability. Furthermore, as an enabling technology, the heater was an incomplete diagnostic solution. Here we describe a more precise, affordable, and robust heater design with thermal standard deviation <0.5°C at operating temperature, a cost of approximately US$.06 per test for heater reaction materials, and an ambient temperature operating range from 16°C to 30°C. We also pair the heater with nucleic acid lateral flow (NALF)-detection for a visual readout. To further illustrate the utility of the electricity-free heater and NALF-detection platform, we demonstrate sensitive and repeatable detection of HIV-1 with a ß-actin positive internal amplification control from processed sample to result in less than 80 minutes. Together, these elements are building blocks for an electricity-free platform capable of isothermal amplification and detection of a variety of pathogens.

Applicability of the National Healthcare Safety Network's surveillance definition of ventilator-associated events in the surgical intensive care unit: a 1-year review.

BACKGROUND: In 2012, the National Healthcare Safety Network presented a new surveillance definition for ventilator-associated events (VAEs) to objectively define worsening pulmonary status in ventilated patients. VAE subcategories, ventilator-associated condition (VAC), infection-related VAC, and probable ventilator-associated pneumonia (PrVAP), were vetted predominantly in medical intensive care units. Our goal was to evaluate how well VAE criteria characterize pulmonary complications in surgical intensive care unit (SICU) patients. METHODS: Since September 2012, all intubated SICU patients were screened prospectively for VAE and monitored for sustained respiratory dysfunction that did not meet VAE criteria. We diagnosed ventilator-associated pneumonia (VAP) using a clinical definition: Clinical Pulmonary Infection Score (CPIS) greater than 6 and catheter-directed bronchoalveolar lavage cultures with 10 or more colony-forming units per milliliter of pathogenic organisms. RESULTS: We admitted 704 intubated patients. A total of 437 were intubated for two or more days (mean [SD], age 46 [18] years; 65% male; median ventilator days, 4 [range, 2-9]; median Sequential Organ Failure Assessment [SOFA] score, 8 [range, 5-10]). Using VAE criteria, we identified 37 patients with VAC, 31 with infection-related VAC, and 22 with PrVAP. While the remaining 400 patients did not meet VAE criteria, we identified 111 patients (28%) with respiratory deterioration and diagnosed 99 additional pneumonias. Of the 111 patients, 85 (77%) never had a period of stable/decreasing oxygenation, requiring elevated vent settings upon initiation of ventilation preventing them from meeting VAE criteria. Of the 99 pneumonia patients, 10% had sustained respiratory deterioration treated with elevations in mean airway pressure; they did not meet VAE criteria as the positive end-expiratory pressure or FIO2 was not elevated. Twenty-seven percent never had a period of stable/decreasing oxygenation. Fifty-eight percent had less than 2 days of respiratory deterioration. Agreement between PrVAP and clinical VAP was 77.3% (κ = 0.243, p < 0.001). CONCLUSION: The applicability of the new National Healthcare Safety Network categories of VAE to critically ill surgery patients is limited. Agreement between PrVAP and clinical VAP in SICU patients is poor. Most surgical patients are not well categorized by this new definition; a better method of surveillance should be created for this patient population. LEVEL OF EVIDENCE: Diagnostic study, level III.

Guiding the management of intubated patients with pneumonia and ventilator-associated events using serial catheter-directed bronchoalveolar lavage.

BACKGROUND: We evaluated the role of serial catheter-directed bronchoalveolar lavage (CDBAL) in the diagnosis and management of pneumonia in ventilated surgical intensive care unit patients. METHODS: Intubated surgical intensive care unit patients were prospectively evaluated with serial CDBALs from September 1, 2012, to May 31, 2013. Initial CDBALs were performed if patients developed the following signs of pneumonia: white blood cell count greater than 11 or less than 4, temperature greater than 38.5°C or less than 36°C, qualitative purulent sputum, worsening oxygenation, or new infiltrate on plain chest x-ray. Subsequent CDBALs were performed every 4 days. Pneumonia was diagnosed using a Clinical Pulmonary Infection Score of greater than 6 and CDBAL cultures with greater than or equal to 10 colony-forming units of pathogenic organisms. Patients were also evaluated for sustained (≥48 hours) respiratory deterioration (increased FIO2 or positive end-expiratory pressure) corresponding to the National Healthcare Safety Network definition of ventilator-associated event (VAE). RESULTS: A total of 159 patients were intubated for 5 days or longer, of whom 80 patients were diagnosed with clinical pneumonia. Of these patients, 67 had serial CDBALs performed, and 81 ventilator-associated pneumonias (VAPs) were diagnosed in these patients. Of the patients with VAP, 16 also met the National Healthcare Safety Network criteria for VAE. Patients with VAP that had sustained respiratory deterioration demonstrated resolution of their compromise 60 hours (interquartile range [IQR], 41-107 hours) after starting antibiotics. Of the patients with pneumonia, 66 (81%) had resolution of the pathogenic bacteria in subsequent CDBAL cultures or were extubated within 4 days (IQR, 4-5 days) after starting antibiotics. The duration of antibiotic therapy in this group was 8 days (IQR, 7-9 days). The remaining 15 patients had multiple positive serial CDBAL cultures that isolated the same organism despite antibiotic treatment. The duration of antibiotic therapy was 14 days (IQR, 10-19 days) in these patients. The culture results were used to adjust antibiotic regimens a median of one time (IQR, 1-2 times) in 13 (87%) and two or more times in 6 (40%) of these patients. CONCLUSION: Serial CDBALs help guide antibiotic treatment duration in patients with pneumonia and VAE. Patients with sustained hypoxia or persistent bacterial growth may require prolonged therapy. LEVEL OF EVIDENCE: Diagnostic test, level III. Therapeutic study, level IV.

The essential role of infection-detection technologies for malaria elimination and eradication.

Recent emphasis on malaria elimination and eradication (E&E) goals is changing the way that experts evaluate malaria diagnostic tools and tactics. As prevalence declines, the focus of malaria management is pivoting toward low-density, subclinical infections and geographically and demographically concentrated reservoirs. These and other changes present challenges and opportunities for innovations in malaria diagnostics aimed at meeting the needs of malaria elimination programs. Developing such technologies requires a review of the operational approaches to detecting malaria infections in areas of declining prevalence. Here we review recent research on epidemiology and biology related to malaria elimination and operational factors that influence E&E strategies. We further propose use-scenarios and a target product profile framework to define and prioritize the required attributes of infection-detection technologies.

Field evaluation of a prototype paper-based point-of-care fingerstick transaminase test.

Monitoring for drug-induced liver injury (DILI) via serial transaminase measurements in patients on potentially hepatotoxic medications (e.g., for HIV and tuberculosis) is routine in resource-rich nations, but often unavailable in resource-limited settings. Towards enabling universal access to affordable point-of-care (POC) screening for DILI, we have performed the first field evaluation of a paper-based, microfluidic fingerstick test for rapid, semi-quantitative, visual measurement of blood alanine aminotransferase (ALT). Our objectives were to assess operational feasibility, inter-operator variability, lot variability, device failure rate, and accuracy, to inform device modification for further field testing. The paper-based ALT test was performed at POC on fingerstick samples from 600 outpatients receiving HIV treatment in Vietnam. Results, read independently by two clinic nurses, were compared with gold-standard automated (Roche Cobas) results from venipuncture samples obtained in parallel. Two device lots were used sequentially. We demonstrated high inter-operator agreement, with 96.3% (95% C.I., 94.3-97.7%) agreement in placing visual results into clinically-defined "bins" (<3x, 3-5x, and >5x upper limit of normal), >90% agreement in validity determination, and intraclass correlation coefficient of 0.89 (95% C.I., 0.87-0.91). Lot variability was observed in % invalids due to hemolysis (21.1% for Lot 1, 1.6% for Lot 2) and correlated with lots of incorporated plasma separation membranes. Invalid rates <1% were observed for all other device controls. Overall bin placement accuracy for the two readers was 84% (84.3%/83.6%). Our findings of extremely high inter-operator agreement for visual reading-obtained in a target clinical environment, as performed by local practitioners-indicate that the device operation and reading process is feasible and reproducible. Bin placement accuracy and lot-to-lot variability data identified specific targets for device optimization and material quality control. This is the first field study performed with a patterned paper-based microfluidic device and opens the door to development of similar assays for other important analytes.

Examination with next-generation sequencing technology of the bacterial microbiota in bronchoalveolar lavage samples after traumatic injury.

BACKGROUND: We examined the microbiota of bronchoalveolar lavage (BAL) samples with next-generation sequencing (NGS) technology to determine whether its results correlate with those of standard culture methods or affect patient outcome or both. METHODS: We collected BAL samples in the surgical intensive care unit (SICU) as part of the standard of care for intubated individuals who had a Clinical Pulmonary Infection Score (CPIS)≥6 points. A portion of the BAL fluid was sequenced for the 16S region of ribosomal deoxyribonucleic acid (rDNA) with the Roche 454 FLX Titanium sequencer. Sequences were analyzed through a data-analysis pipeline to identify the appropriate taxonomic designation (∼species) of each 16s sequence. The bacterial microbiota of each BAL sample was compared with the bacteria identified in the sample through standard culture methods. Correlations between the taxonomic diversity of the microbiota and clinical outcome were examined through linear regression and Pearson correlation. RESULTS: Bronchoalveolar lavage samples from 12 individuals in the SICU who had a CPIS≥6 points were examined through 454 pyrosequencing. The number of phylotypes (∼species) in the samples ranged from 15 to 129. The number of phyla in the BAL samples ranged from 3 to 14. There was little correlation between the bacteria identified by NGS and those identified with standard culture methods. The same predominant bacterial strain was identified by both culture and sequencing in only a single sample. The correlation between patient days on a ventilator and the number of species in BAL samples was significant (r=0.7435, p=0.0056; r2=0.5528). CONCLUSIONS: Increasing diversity of the bacterial microbiota in BAL samples correlates with the duration of mechanical ventilation. Bacteria identified through standard culture methods were not well correlated with the findings of NGS.

Early nonbronchoscopic bronchoalveolar lavage: predictor of ventilator-associated pneumonia?

BACKGROUND: Ventilator-associated pneumonia is a problem in trauma and emergency general surgery patients. Our hospital-acquired infection prevention committee approved the use of early nonbronchoscopic bronchoalveolar lavage (screening-BAL) in the surgical intensive care unit (SICU) to identify ventilated patients with bronchiolar bacteria before 48 hours. We reviewed the results of this quality improvement initiative. METHODS: All ventilated patients in the SICU (March 2011 to June 2012) underwent a screening-BAL 36 hours to 48 hours after intubation; quantitative culture results (>5 × 10(4) colony-forming unit per milliliter) were used to identify positive specimens. Clinical pneumonia was defined as clinical pulmonary infection score greater than 6 with a subsequent positive diagnostic-BAL result. Sequential organ failure assessment scores were averaged for the first 48 hours in the SICU. Continuous and dichotomous data were compared, and a multivariate regression analysis was performed on the screening-BAL and pneumonia results. RESULTS: Screening-BALs were performed in 150 patients (99 trauma and 51 emergency general surgery patients), 72 of these specimens had positive findings. Fifty-three clinical pneumonias were diagnosed, and 45 (positive predictive value, 0.85) identified the same organism as the screening-BAL. Clinical pneumonia developed in eight patients with a negative screening-BAL (negative predictive value, 0.85). Antibiotic therapy at the time of the screening-BAL was associated with a negative screen (odds ratio, 0.44; p = 0.026). Pneumonia developed on median postintubation Day 4 (2-15 days) in patients with a positive screening-BAL results as compared with day 7.5 in the patients with a negative screening-BAL results (3.5-15 days; p = 0.007). Field intubation is an independent risk factor (odds ratio, 3.5; p = 0.004). CONCLUSION: Positive screening-BAL results in trauma and emergency general surgery patients are associated with the development of ventilator-associated pneumonia by the same organism and may play a role in identifying patients at risk for pneumonia. Further studies must be conducted to evaluate the role of screening-BAL in this patient population. LEVEL OF EVIDENCE: Diagnostic/prognostic study, level III.

Emerging technologies for point-of-care CD4 T-lymphocyte counting.

A CD4 T-lymphocyte count determines eligibility for antiretroviral therapy (ART) in patients recently diagnosed with HIV and also monitors the efficacy of ART treatment thereafter. ART slows the progression of HIV to AIDS. In the developing world, CD4 tests are often performed in centralized laboratories, typically in urban areas. The expansion of ART programs into rural areas has created a need for rapid CD4 counting because logistical barriers can delay the timely dissemination of test results and affect patient care through delay in intervention or loss of follow-up care. CD4 measurement at the point-of-care (POC) in rural areas could help the facilitation of ART and monitoring of treatment. This review highlights recent technology developments with applications towards determining CD4 counts at the POC.

A simple, inexpensive device for nucleic acid amplification without electricity-toward instrument-free molecular diagnostics in low-resource settings.

BACKGROUND: Molecular assays targeted to nucleic acid (NA) markers are becoming increasingly important to medical diagnostics. However, these are typically confined to wealthy, developed countries; or, to the national reference laboratories of developing-world countries. There are many infectious diseases that are endemic in low-resource settings (LRS) where the lack of simple, instrument-free, NA diagnostic tests is a critical barrier to timely treatment. One of the primary barriers to the practicality and availability of NA assays in LRS has been the complexity and power requirements of polymerase chain reaction (PCR) instrumentation (another is sample preparation). METHODOLOGY/PRINCIPAL FINDINGS: In this article, we investigate the hypothesis that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays. We assess the heater's equivalence to commercially available PCR instruments through the characterization of the temperature profiles produced, and a minimal method comparison. Versions of the prototype for several different isothermal techniques are presented. CONCLUSIONS/SIGNIFICANCE: We demonstrate that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays, and that the results of those assays are not significantly different from ones incubated in parallel in commercially available PCR instruments. These results clearly suggest the potential of the non-instrumented nucleic acid amplification (NINA) heater for molecular diagnostics in LRS. When combined with other innovations in development that eliminate power requirements for sample preparation, cold reagent storage, and readout, the NINA heater will comprise part of a kit that should enable electricity-free NA testing for many important analytes.

Instrument-free nucleic acid amplification assays for global health settings.

Many infectious diseases that affect global health are most accurately diagnosed through nucleic acid amplification and detection. However, existing nucleic acid amplification tests are too expensive and complex for most low-resource settings. The small numbers of centralized laboratories that exist in developing countries tend to be in urban areas and primarily cater to the affluent. In contrast, rural area health care facilities commonly have only basic equipment and health workers have limited training and little ability to maintain equipment and handle reagents.1 Reliable electric power is a common infrastructure shortfall. In this paper, we discuss a practical approach to the design and development of non-instrumented molecular diagnostic tests that exploit the benefits of isothermal amplification strategies. We identify modular instrument-free technologies for sample collection, sample preparation, amplification, heating, and detection. By appropriately selecting and integrating these instrument-free modules, we envision development of an easy to use, infrastructure independent diagnostic test that will enable increased use of highly accurate molecular diagnostics at the point of care in low-resource settings.

Use of an alternative scale-down approach to predict and extend hydroxyapatite column lifetimes.

Ceramic hydroxyapatite (CHT) chromatography offers unique selectivity for protein purification. However, columns composed of CHT, a crystalline form of calcium phosphate, often suffer from short column lifetimes, particularly under acidic operating conditions. In this paper, CHT was used under slightly acidic conditions (pH 6) for the production scale purification of a recombinant protein. Under these conditions, the packing quality of production scale CHT columns (45 cm diameter) degraded after 5-10 cycles of operation. This was not reproduced using a conventional scale-down chromatography model, in which a constant column bed height was maintained across scales. Thus, an alternative scale-down model was developed to better predict the lifetime of large scale CHT columns. The alternative approach, which utilized a constant column diameter-to-height aspect ratio, was able to predict column failure that approximated that of the manufacturing scale column. The alternative scale-down approach was then used to test alternate buffer formulations that significantly improved the CHT column lifetime. Screening studies, which assessed the effects of mobile phase pH and composition on the dissolution (weight loss) of CHT, were used to identify the alternative mobile phase formulations. Results from the study showed that slight changes to the existing mobile phase compositions significantly increased the column lifetime, from approximately 10 cycles to approximately 65 cycles of use, without altering the purification of the recombinant protein. The alternative scale-down model, together with relatively rapid mobile phase screening studies, provides a practical approach for predicting and optimizing the useful lifetime of CHT columns for large scale applications.

A method for characterizing adsorption of flowing solutes to microfluidic device surfaces.

We present a method for characterizing the adsorption of solutes in microfluidic devices that is sensitive to both long-lived and transient adsorption and can be applied to a variety of realistic device materials, designs, fabrication methods, and operational parameters. We have characterized the adsorption of two highly adsorbing molecules (FITC-labeled bovine serum albumin (BSA) and rhodamine B) and compared these results to two low adsorbing species of similar molecular weights (FITC-labeled dextran and fluorescein). We have also validated our method by demonstrating that two well-known non-fouling strategies [deposition of the polyethylene oxide (PEO)-like surface coating created by radio-frequency glow discharge plasma deposition (RF-GDPD) of tetraethylene glycol dimethyl ether (tetraglyme, CH(3)O(CH(2)CH(2)O)(4)CH(3)), and blocking with unlabeled BSA] eliminate the characteristic BSA adsorption behavior observed otherwise.

Diffusion based analysis in a sheath flow microchannel: the sheath flow T-sensor.

This paper describes a microfluidic channel that allows for diffusion-based analysis of adsorbing species without passivation of the channel surfaces. The sheath flow configuration was used to measure the diffusion coefficient of fluorescently labeled species from their spatial distribution within the microchannel by analyzing the derivative of the intensity profile at the interface between two distinct core fluids. Measurements for both a small molecule (rhodamine B) and an intermediate-sized protein (wheat germ agglutinin) were made, demonstrating the utility of the sheath flow T-sensor.

Tracheostomy timing and the duration of weaning in patients with acute respiratory failure.

INTRODUCTION: The effect of various airway management strategies, such as the timing of tracheostomy, on liberation from mechanical ventilation (MV) is uncertain. We tested the hypothesis that tracheostomy, when performed prior to active weaning, does not influence the duration of weaning or of MV in comparison with a more selective use of tracheostomy. PATIENTS AND METHODS: In this observational prospective cohort study, surgical patients requiring >or= 72 hours of MV were followed prospectively. Patients undergoing tracheostomy prior to any active weaning attempts (early tracheostomy [ET]) were compared with patients in whom initial weaning attempts were made with the endotracheal tube in place (selective tracheostomy [ST]). RESULTS: We compared the duration of weaning, the total duration of MV and the frequency of fatigue and pneumonia. Seventy-four patients met inclusion criteria. Twenty-one patients in the ET group were compared with 53 patients in the ST group (47% of whom ultimately underwent tracheostomy). The median duration of weaning was shorter (3 days versus 6 days, P = 0.05) in patients in the ET group than in the ST group, but the duration of MV was not (median [interquartile range], 11 days [9-26 days] in the ET group versus 13 days [8-21 days] in the ST group). The frequencies of fatigue and pneumonia were lower in the ET group patients. DISCUSSION: Determining the ideal timing of tracheostomy in critically ill patients has been difficult and often subjective. To standardize this process, it is important to identify objective criteria to identify patients most likely to benefit from the procedure. Our data suggest that in surgical patients with resolving respiratory failure, a patient who meets typical criteria for a trial of spontaneous breathing but is not successfully extubated within 24 hours may benefit from a tracheostomy. Our data provide a framework for the conduct of a clinical trial in which tracheostomy timing can be assessed for its impact on the duration of weaning. CONCLUSION: Tracheostomy prior to active weaning may hasten liberation from ventilation and reduce complications. However, this does not reduce the overall duration of MV.

Controlled microfluidic reconstitution of functional protein from an anhydrous storage depot.

A novel method has been developed for preserving molecules in microfluidic devices that also enables the control of the spatial and temporal concentrations of the reconstituted molecules within the devices. In this method, a storage cavity, embedded in a microchannel, is filled with a carbohydrate matrix containing, for example, a reagent. When the matrix is exposed to flowing liquid, it dissolves, resulting in the controlled reconstitution and release of the reagent from the cavity. The technique was demonstrated using two different model systems; the successful preservation and controlled release of beta-galactosidase was achieved. This method has possible applications for simple point-of-care drug delivery and immunoassays, and could be used to pattern the surfaces of microchannels. More broadly, this preservation and controlled release technique can be applied where the preservation and/or spatial and temporal control of chemical concentrations are desired.

Nonlinear decrease of background fluorescence in polymer thin-films - a survey of materials and how they can complicate fluorescence detection in microTAS.

Polymers and plastics are receiving increased attention as materials for microfluidics and microTAS applications. Given the ubiquity of fluorescence detection techniques in micro-analytical systems, the fluorescence properties of polymers and plastics should not be overlooked. We survey some commonly available polymer thin-films for their fluorescence behaviour under standardized conditions to determine which materials are most suitable for high-sensitivity fluorescence detection lab chips. The initial fluorescence intensities of some of the materials surveyed were significantly higher than glass and fused silica controls, and decreased over the three hour period with complex kinetics. We then discuss how this has confounded fluorescence detection in our analytical context, and possible mechanisms for the decrease.