Implementation of an efficient SARS-CoV-2 specimen pooling strategy for high throughput diagnostic testing

The rapid identification and isolation of infected individuals remains a key strategy for controlling the spread of SARS-CoV-2. Frequent testing of populations to detect infection early in asymptomatic or presymptomatic individuals can be a powerful tool for intercepting transmission, especially when the viral prevalence is low. However, RT-PCR testing-the gold standard of SARS-CoV-2 diagnosis-is expensive, making regular testing of every individual unfeasible. Sample pooling is one approach to lowering costs. By combining samples and testing them in groups the number of tests required is reduced, substantially lowering costs. Here we report on the implementation of pooling strategies using 3-d and 4-d hypercubes to test a professional sports team in South Africa. We have shown that infected samples can be reliably detected in groups of 27 and 81, with minimal loss of assay sensitivity for samples with individual Ct values of up to 32. We report on the automation of sample pooling, using a liquid-handling robot and an automated web interface to identify positive samples. We conclude that hypercube pooling allows for the reliable RT-PCR detection of SARS-CoV-2 infection, at significantly lower costs than lateral flow antigen (LFA) tests.

Optimal uses of pooled testing for COVID-19 incorporating imperfect test performance and pool dilution effect: An application to congregate settings in Los Angeles County

INTRODUCTION

Pooled testing is a potentially efficient alternative strategy for COVID-19 testing in congregate settings. We evaluated the utility and cost-savings of pooled testing based on imperfect test performance and potential dilution effect due to pooling and created a practical calculator for online use.

METHODS

We developed a 2-stage pooled testing model accounting for dilution. The model was applied to hypothetical scenarios of 100 specimens collected during a one-week time-horizon cycle for varying levels of COVID-19 prevalence and test sensitivity and specificity, and to 338 skilled nursing facilities (SNFs) in Los Angeles County (Los Angeles) (data collected and analyzed in 2020).

RESULTS

Optimal pool sizes ranged from 1 to 12 in instances where there is a least one case in the batch of specimens. 40% of Los Angeles SNFs had more than one case triggering a response-testing strategy. The median number (minimum; maximum) of tests performed per facility were 56 (14; 356) for a pool size of 4, 64 (13; 429) for a pool size of 10, and 52 (11; 352) for an optimal pool size strategy among response-testing facilities. The median costs of tests in response-testing facilities were $8250 ($1100; $46,100), $6000 ($1340; $37,700), $6820 ($1260; $43,540), and $5960 ($1100; $37,380) when adopting individual testing, a pooled testing strategy using pool sizes of 4, 10, and optimal pool size, respectively.

CONCLUSIONS

Pooled testing is an efficient strategy for congregate settings with a low prevalence of COVID-19. Dilution as a result of pooling can lead to erroneous false-negative results.

Development of an alternative saliva test for diagnosis of SARS-CoV-2 using TRIzol: Adapting to countries with lower incomes looking for a large-scale detection program

The use of saliva for the diagnosis of SARS-CoV-2 has shown to be a good alternative to nasopharyngeal swabs (NPS), since it permits self-collection, avoids the exposure of healthy persons to infected patients, reduces waiting times, eliminates the need of personal protective equipment and is non-invasive. Yet current saliva testing is still expensive due to the need of specialized tubes containing buffers to stabilize the RNA of SARS-CoV-2 and inactivate the virus. These tubes are expensive and not always accessible in sufficient quantities. We now developed an alternative saliva testing method, using TRIzol for extraction, viral inactivation, and storage of SARS-CoV-2 RNA, combined with RT-qPCR, which was comparable in its performance to NPS. Paired saliva samples and NPS were taken from 15 asymptomatic healthcare workers and one patient with SARS-CoV-2. Further 13 patients with SARS-CoV-2 were only saliva-tested. All the tests were performed according to CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel. Saliva (4 mL) was taken in sterile 50 mL tubes, 1.5 mL TRIzol were added and mixed. Our results show that 5 μL of saliva RNA extracted with TRIzol allow for an adequate detection of the virus in patients positive for SARS-CoV-2 and was equally sensitive to NPS in TRIzol. We conclude that saliva testing using TRIzol is a recommendable method for diagnosis of SARS-CoV-2 since it has several advantages over currently used saliva tests: it can be done with normal sterile tubes, does not need cold-chain handling, is stable at room temperature, is non-invasive and less costly, making it more accessible for low-income countries. Cheaper saliva testing using TRIzol is especially relevant for low-income countries to optimize diagnosis and help define quarantine durations for families, healthcare workers, schools, and other public workplaces, thus decreasing infections and mortality caused by SARS-CoV-2.

Cost-effectiveness analysis of primary human papillomavirus testing in cervical cancer screening: Results from the HPV FOCAL Trial

The Human Papillomavirus FOr CervicAL cancer (HPV FOCAL) trial is a large randomized controlled trial comparing the efficacy of primary HPV testing to cytology among women in the population-based Cervix Screening Program in British Columbia, Canada. We conducted a cost-effectiveness analysis based on the HPV FOCAL trial to estimate the incremental cost per detected high-grade cervical intraepithelial neoplasia of grade 2 or worse lesions (CIN2+). A total of 19,009 women aged 25 to 65 were randomized to one of two study groups. Women in the intervention group received primary HPV testing with reflex liquid-based cytology (LBC) upon a positive finding with a screening interval of 48 months. Women in the control group received primary LBC testing, and those negative returned at 24 months for LBC and again at 48 months for exit screening. Both groups received HPV and LBC co-testing at the 48-month exit. Incremental costs during the course of the trial were comparable between the intervention and control groups. The intervention group had lower overall costs and detected a larger number of CIN2+ lesions, resulting in a lower mean cost per CIN2+ detected ($7551) than the control group ($8325), a difference of -$773 [all costs in 2018 USD]. Cost per detected lesion was sensitive to the costs of sample collection, HPV testing, and LBC testing. The HPV FOCAL Trial results suggest that primary HPV testing every 4 years produces similar outcomes to LBC-based testing every 2 years for cervical cancer screening at a lower cost.

Stability of SARS-CoV-2 RNA in Nonsupplemented Saliva

The expense of saliva collection devices designed to stabilize severe acute respiratory syndrome coronavirus 2 RNA is prohibitive to mass testing. However, virus RNA in nonsupplemented saliva is stable for extended periods and at elevated temperatures. Simple plastic tubes for saliva collection will make large-scale testing and continued surveillance easier.

Cost-Effectiveness of Offering Cervical Cancer Screening with HPV Self-Sampling among African-American Women in the Mississippi Delta

BACKGROUND

African-American women in the United States have an elevated risk of cervical cancer incidence and mortality. In the Mississippi Delta, cervical cancer disparities are particularly stark.

METHODS

We conducted a micro-costing study alongside a group randomized trial that evaluated the efficacy of a patient-centered approach ("Choice" between self-collection at home for HPV testing or current standard of care within the public health system in Mississippi) versus the current standard of care ["Standard-of-care screening," involving cytology (i.e., Pap) and HPV co-testing at the Health Department clinics]. The interventions in both study arms were delivered by community health workers (CHW). Using cost, screening uptake, and colposcopy adherence data from the trial, we informed a mathematical model of HPV infection and cervical carcinogenesis to conduct a cost-effectiveness analysis comparing the "Choice" and "Standard-of-care screening" interventions among un/underscreened African-American women in the Mississippi Delta.

RESULTS

When each intervention was simulated every 5 years from ages 25 to 65 years, the "Standard-of-care screening" strategy reduced cancer risk by 6.4% and was not an efficient strategy; "Choice" was more effective and efficient, reducing lifetime risk of cervical cancer by 14.8% and costing $62,720 per year of life saved (YLS). Screening uptake and colposcopy adherence were key drivers of intervention cost-effectiveness.

CONCLUSIONS

Offering "Choice" to un/underscreened African-American women in the Mississippi Delta led to greater uptake than CHW-facilitated screening at the Health Department, and may be cost-effective.

IMPACT

We evaluated the cost-effectiveness of an HPV self-collection intervention to reduce disparities.

Evaluation of sample pooling for screening of SARS CoV-2

Background

The coronavirus disease 2019 (COVID-19) pandemic has revealed the global public health importance of robust diagnostic testing. To overcome the challenge of nucleic acid (NA) extraction and testing kit availability, an efficient method is urgently needed.

Objectives

To establish an efficient, time and resource-saving and cost-effective methods, and to propose an ad hoc pooling approach for mass screening of SARS-CoV-2.

Methods

We evaluated pooling approach on both direct clinical and NA samples. The standard reverse transcriptase polymerase chain reaction (RT-PCR) test of the SARS CoV-2 was employed targeting the nucleocapsid (N) and open reading frame (ORF1ab) genomic region of the virus. The experimental pools were created using SARS CoV-2 positive clinical samples and extracted RNA spiked with up to 9 negative samples. For the direct clinical samples viral NA was extracted from each pool to a final extraction volume of 200μL, and subsequently both samples tested using the SARS CoV-2 RT-PCR assay.

Results

We found that a single positive sample can be amplified and detected in pools of up to 7 samples depending on the cycle threshold (Ct) value of the original sample, corresponding to high, and low SARS CoV-2 viral copies per reaction. However, to minimize false negativity of the assay with pooling strategies and with unknown false negativity rate of the assay under validation, we recommend pooling of 4/5 in 1 using the standard protocols of the assay, reagents and equipment. The predictive algorithm indicated a pooling ratio of 5 in 1 was expected to retain accuracy of the test irrespective of the Ct value samples spiked, and result in a 137% increase in testing efficiency.

Conclusions

The approaches showed its concept in easily customized and resource-saving manner and would allow expanding of current screening capacities and enable the expansion of detection in the community. We recommend clinical sample pooling of 4 or 5 in 1. However, we don’t advise pooling of clinical samples when disease prevalence is greater than 7%; particularly when sample size is large.

Feasibility of Embedding a Scalable, Virtually Enabled Biorepository in the Electronic Health Record for Precision Medicine

Importance

A cornerstone of precision medicine is the identification and use of biomarkers that help subtype patients for targeted treatment. Such an approach requires the development and subsequent interrogation of large-scale biobanks linked to well-annotated clinical data. Traditional means of creating these data-linked biobanks are costly and lengthy, especially in acute conditions that require time-sensitive clinical data and biospecimens.

Objectives

To develop a virtually enabled biorepository and electronic health record (EHR)-embedded, scalable cohort for precision medicine (VESPRE) and compare the feasibility, enrollment, and costs of VESPRE with those of a traditional study design in acute care.

Design, Setting, and Participants

In a prospective cohort study, the EHR-embedded screening alert was generated for 3428 patients, and 2199 patients (64%) were eligible and screened. Of these, 1027 patients (30%) were enrolled. VESPRE was developed for regulatory compliance, feasibility, internal validity, and cost in a prospective cohort of 1027 patients (aged ≥18 years) with sepsis-3 within 6 hours of presentation to the emergency department. The VESPRE infrastructure included (1) automated EHR screening, (2) remnant blood collection for creation of a virtually enabled biorepository, and (3) automated clinical data abstraction. The study was conducted at an academic institution in southwestern Pennsylvania from October 17, 2017, to June 6, 2019.

Main Outcomes and Measures

Regulatory compliance, enrollment, internal validity of automated screening, biorepository acquisition, and costs.

Results

Of the 1027 patients enrolled in the study, 549 were included in the proof-of-concept analysis (305 [56%] men); median (SD) age was 59 (17) years. VESPRE collected 12 963 remnant blood and urine samples and demonstrated adequate feasibility for clinical, biomarker, and microbiome analyses. Over the 20-month test, the total cost beyond the existing operations infrastructure was $39 417.50 ($14 880.00 project management, $22 717.50 laboratory supplies/staff, and $1820.00 data management)-approximately $39 per enrolled patient vs $239 per patient for a traditional cohort study.

Conclusions and Relevance

Results of this study suggest that, in a large US health system that collects data using a common EHR platform and centralized laboratory system, VESPRE, a large-scale, inexpensive EHR-embedded infrastructure for precision medicine can be used. Tested in the sepsis setting, VESPRE appeared to capture a high proportion of eligible patients at low incremental cost.

Solvent-free, Noncontact Electrostatic Sampling for Rapid Analysis with Mass Spectrometry: Application to Drugs and Explosives

A hand-held Van de Graaf generator is used to apply a high voltage, negligible current electrostatic potential to a wire mesh positioned in close proximity to a particle-laden surface in order to collect those particles for analysis. The electrostatic field effects transfer particles to the mesh without a requirement for mechanical contact between mesh and surface. Analysis of chemicals present in the sampled particles is completed by thermal desorption electrospray ionization. The utility of the method for noncontact sampling is demonstrated using solid drug powder samples, and inorganic explosives dispersed either on solid surfaces or in sand/soil in order to simulate common interfering matrices that might be encountered in the forensic environment. A metal mesh sampling substrate is utilized instead of traditional polymer-based swabs in order to permit thermal desorption at higher temperatures. The method leaves no visible trace of sampling leaving details such as a fingerprint image unperturbed, as demonstrated using fluorescence photography. Direct sampling of trace particles from hard surfaces and skin documents flexibility in the choice of sampling substrates, desorption temperatures, and sampling times. The potential of the device for use in forensic analyses is detailed.

Cost-effectiveness analysis of repeated self-sampling for HPV testing in primary cervical screening: a randomized study

BACKGROUND

Human papillomavirus (HPV) testing is recommended in primary cervical screening to improve cancer prevention. An advantage of HPV testing is that it can be performed on self-samples, which could increase population coverage and result in a more efficient strategy to identify women at risk of developing cervical cancer. Our objective was to assess whether repeated self-sampling for HPV testing is cost-effective in comparison with Pap smear cytology for detection of cervical intraepithelial neoplasia grade 2 or more (CIN2+) in increasing participation rate in primary cervical screening.

METHODS

A cost-effectiveness analysis (CEA) was performed on data from a previously published randomized clinical study including 36,390 women aged 30-49 years. Participants were randomized either to perform repeated self-sampling of vaginal fluid for HPV testing (n = 17,997, HPV self-sampling arm) or to midwife-collected Pap smears for cytological analysis (n = 18,393, Pap smear arm).

RESULTS

Self-sampling for HPV testing led to 1633 more screened women and 107 more histologically diagnosed CIN2+ at a lower cost vs. midwife-collected Pap smears (€ 229,446 vs. € 782,772).

CONCLUSIONS

This study resulted in that repeated self-sampling for HPV testing increased participation and detection of CIN2+ at a lower cost than midwife-collected Pap smears in primary cervical screening. Offering women a home-based self-sampling may therefore be a more cost-effective alternative than clinic-based screening.

TRIAL REGISTRATION

Not registered since this trial is a secondary analysis of an earlier published study (Gustavsson et al., British journal of cancer. 118:896-904, 2018).

Cost-effective homemade automatically opening endobag for video-assisted thoracic surgery

Because specimen removal is often required during video-assisted thoracic surgery, an easily produced, simple-to-use and cost-effective endobag is necessary to avoid wound metastasis. However, commercial endobags are expensive. Here I describe a homemade automatically opening, cost-effective, safe and easily produced endobag for video-assisted thoracic surgery that is suitable for use in low-income locations with limited health budgets.

Pooling as a strategy for the timely diagnosis of soil-transmitted helminths in stool: value and reproducibility

BACKGROUND

The strategy of pooling stool specimens has been extensively used in the field of parasitology in order to facilitate the screening of large numbers of samples whilst minimizing the prohibitive cost of single sample analysis. The aim of this study was to develop a standardized reproducible pooling protocol for stool samples, validated between two different laboratories, without jeopardizing the sensitivity of the quantitative polymerase chain reaction (qPCR) assays employed for the detection of soil-transmitted helminths (STHs). Two distinct experimental phases were recruited. First, the sensitivity and specificity of the established protocol was assessed by real-time PCR for each one of the STHs. Secondly, agreement and reproducibility of the protocol between the two different laboratories were tested. The need for multiple stool sampling to avoid false negative results was also assessed. Finally, a cost exercise was conducted which included labour cost in low- and high-wage settings, consumable cost, prevalence of a single STH species, and a simple distribution pattern of the positive samples in pools to estimate time and money savings suggested by the strategy.

RESULTS

The sensitivity of the pooling method was variable among the STH species but consistent between the two laboratories. Estimates of specificity indicate a 'pooling approach' can yield a low frequency of 'missed' infections. There were no significant differences regarding the execution of the protocol and the subsequent STH detection between the two laboratories, which suggests in most cases the protocol is reproducible by adequately trained staff. Finally, given the high degree of agreement, there appears to be little or no need for multiple sampling of either individuals or pools.

CONCLUSIONS

Our results suggest that the pooling protocol developed herein is a robust and efficient strategy for the detection of STHs in 'pools-of-five'. There is notable complexity of the pool preparation to ensure even distribution of helminth DNA throughout. Therefore, at a given setting, cost of labour among other logistical and epidemiological factors, is the more concerning and determining factor when choosing pooling strategies, rather than losing sensitivity and/or specificity of the molecular assay or the method.

Touch Imprint Cytology: A Rapid and Accurate Method for Diagnosis of Oral Cancer

OBJECTIVES

Touch imprint cytology (TIC) is a rapid and cheap method and can be used as an adjunct to biopsy for the evaluation of suspected malignancy. We evaluated the advantages and limitations of TIC for the preoperative diagnosis of oral squamous cell carcinoma.

STUDY DESIGN

We used 280 incisional biopsies of clinically suspected oral squamous cell carcinoma and compared TIC diagnosis to histopathological sections. The sensitivity, specificity, and diagnostic accuracy of TIC were evaluated.

RESULTS

A total of 201 (82.5%) cases were diagnosed as malignant, 22 (7.9%) cases were diagnosed as suspicious of malignancy, and 54 (19.3%) cases as benign/negative on TIC. The overall sensitivity of TIC was 98.2%, specificity was 89.3%, the positive-predictive value 97.3%, and the negative-predictive value was 92.6%. The accuracy of the test was 96.4%.

CONCLUSIONS

TIC is an accurate, simple, rapid, and cost-effective method that aids the diagnosis of oral squamous cell carcinoma but does not replace incisional biopsy. The cytologic examination of imprints of biopsies also helps determine the adequacy of the specimen for histologic examination.

Calculating the prevalence of soil-transmitted helminth infection through pooling of stool samples: Choosing and optimizing the pooling strategy

Prevalence is a common epidemiological measure for assessing soil-transmitted helminth burden and forms the basis for much public-health decision-making. Standard diagnostic techniques are based on egg detection in stool samples through microscopy and these techniques are known to have poor sensitivity for individuals with low infection intensity, leading to poor sensitivity in low prevalence populations. PCR diagnostic techniques offer very high sensitivities even at low prevalence, but at a greater cost for each diagnostic test in terms of equipment needed and technician time and training. Pooling of samples can allow prevalence to be estimated while minimizing the number of tests performed. We develop a model of the relative cost of pooling to estimate prevalence, compared to the direct approach of testing all samples individually. Analysis shows how expected relative cost depends on both the underlying prevalence in the population and the size of the pools constructed. A critical prevalence level (approx. 31%) above which pooling is never cost effective, independent of pool size. When no prevalence information is available, there is no basis on which to choose between pooling and testing all samples individually. We recast our model of relative cost in a Bayesian framework in order to investigate how prior information about prevalence in a given population can be used to inform the decision to choose either pooling or full testing. Results suggest that if prevalence is below 10%, a relatively small exploratory prevalence survey (10-15 samples) can be sufficient to give a high degree of certainty that pooling may be relatively cost effective.

Evaluating turnaround times for early infant diagnosis samples in Kenya from 2011-2014: A retrospective analysis of HITSystem program data

Long turnaround times (TAT) for the processing and posting of results of infant HIV DNA PCR samples can hinder the success of early infant diagnosis (EID) programs. The HITSystem is an eHealth intervention that alerts staff when services are overdue or results are delayed. We conducted a retrospective analysis of 3669 HIV-exposed infants enrolled in 15 Kenya hospital EID programs and three laboratories using the HITSystem from 2011–2014. We assessed mean and median TAT from when a sample was: 1) obtained to when it was shipped to the laboratory, 2) shipped to when it was received at the laboratory, 3) received to when a result was posted, and 4) the total time from obtaining the sample (step 1) to posting the result (step 3). TAT were compared by laboratory, clinic, year, and month of sample collection. 3625 infant samples had results posted by end of 2014. Mean TAT from sample collection to shipping was 5.2 days, from shipping to laboratory receipt was 2.0 days, and from laboratory receipt to result posting was 17.4 days. Altogether, it took an average of 24.7 days from sample collection until result posting. There was significant variation between laboratories, particularly in laboratory processing times (step 3). TAT showed a decreasing trend from 2011–2014, although TAT in December remained higher. Compared with other Kenyan studies, TAT in these HITSystem enrolled settings were shorter. Significant variation between laboratories, however, indicates the need to strengthen protocols and infrastructure to ensure that all laboratories can provide rapid, high-quality services.

Environmental DNA from Residual Saliva for Efficient Noninvasive Genetic Monitoring of Brown Bears (Ursus arctos)

Noninvasive genetic sampling is an important tool in wildlife ecology and management, typically relying on hair snaring or scat sampling techniques, but hair snaring is labor and cost intensive, and scats yield relatively low quality DNA. New approaches utilizing environmental DNA (eDNA) may provide supplementary, cost-effective tools for noninvasive genetic sampling. We tested whether eDNA from residual saliva on partially-consumed Pacific salmon (Oncorhynchus spp.) carcasses might yield suitable DNA quality for noninvasive monitoring of brown bears (Ursus arctos). We compared the efficiency of monitoring brown bear populations using both fecal DNA and salivary eDNA collected from partially-consumed salmon carcasses in Southeast Alaska. We swabbed a range of tissue types from 156 partially-consumed salmon carcasses from a midseason run of lakeshore-spawning sockeye (O. nerka) and a late season run of stream-spawning chum (O. keta) salmon in 2014. We also swabbed a total of 272 scats from the same locations. Saliva swabs collected from the braincases of salmon had the best amplification rate, followed by swabs taken from individual bite holes. Saliva collected from salmon carcasses identified unique individuals more quickly and required much less labor to locate than scat samples. Salmon carcass swabbing is a promising method to aid in efficient and affordable monitoring of bear populations, and suggests that the swabbing of food remains or consumed baits from other animals may be an additional cost-effective and valuable tool in the study of the ecology and population biology of many elusive and/or wide-ranging species.

Colonization Status and Appropriate Antibiotic Therapy for Nosocomial Bacteremia Caused by Antibiotic-Resistant Gram-Negative Bacteria in an Intensive Care Unit

Objective:

Timely initiation of antibiotic therapy is crucial for severe infection. Appropriate antibiotic therapy is often delayed for nosocomial infections caused by antibiotic-resistant bacteria. The relationship between knowledge of colonization caused by antibiotic-resistant gram-negative bacteria (ABR-GNB) and rate of appropriate initial antibiotic therapy for subsequent bacteremia was evaluated.

Design:

Retrospective cohort study.

Setting:

Fifty-four-bed intensive care unit (ICU) of a university hospital. In this unit, colonization surveillance is performed through routine site-specific surveillance cultures (urine, mouth, trachea, and anus). Additional cultures are performed when presumed clinically relevant.

Patients:

ICU patients with nosocomial bacteremia caused by ABR-GNB.

Results:

Infectious and microbiological characteristics and rates of appropriate antibiotic therapy were compared between patients with and without colonization prior to bacteremia. Prior colonization was defined as the presence (detected ≥ 2 days before the onset of bacteremia) of the same ABR-GNB in colonization and subsequent blood cultures. During the study period, 157 episodes of bacteremia caused by ABR-GNB were suitable for evaluation. One hundred seventeen episodes of bacteremia (74.5%) were preceded by colonization. Appropriate empiric antibiotic therapy (started within 24 hours) was administered for 74.4% of these episodes versus 55.0% of the episodes that occurred without prior colonization. Appropriate therapy was administered within 48 hours for all episodes preceded by colonization versus 90.0% of episodes without prior colonization.

Conclusion:

Knowledge of colonization status prior to infection is associated with higher rates of appropriate therapy for patients with bacteremia caused by ABR-GNB (Infect Control Hosp Epidemiol 2005;26:575-579).

Monitoring the use of anatomical teaching material using a low-cost radio frequency identification system: A comprehensive assessment

The correct tracking and monitoring of anatomical specimens is not only imperative in any modern body donation programs but also in any universities for which teaching the next generation of health care professionals is the primary mission. This has long been an arduous process for anatomy institutions across the world, and the recent focus of new curricula on self-directed learning adds new stress on specimens which are used by students. The radio frequency identification (RFID) technology has been proposed as a very effective tracking system in healthcare considering that it enables automatic identification and data capture of multiple items at once. In this study, the feasibility of a low-cost RFID inventory system is assessed, from its design to the performance of commercially available RFID tags in a gross anatomy laboratory. The results show that ultrahigh frequency-based RFID tags successfully performed when attached to a collection of 112 plastinated and 280 wet dissected specimens. Comparison analysis of different tags reveals, however, that careful selection of RFID tags needs to be considered when wet specimens need to be tracked as preservation fluids can absorb radio waves energy. This study demonstrates that it is economically feasible to incorporate RFID technology to closely monitor the use of anatomical teaching specimens. The described RFID inventory system was not only able to preserve the integrity of the specimens being used by limiting handling and therefore human error but was also able to identify missing or misplaced specimens and to update their status.

Using Exclusion-Based Sample Preparation (ESP) to Reduce Viral Load Assay Cost

Viral load (VL) measurements are critical to the proper management of HIV in developing countries. However, access to VL assays is limited by the high cost and complexity of existing assays. While there is a need for low cost VL assays, performance must not be compromised. Thus, new assays must be validated on metrics of limit of detection (LOD), accuracy, and dynamic range. Patient plasma samples from the Joint Clinical Research Centre in Uganda were de-identified and measured using both an existing VL assay (Abbott RealTime HIV-1) and our assay, which combines low cost reagents with a simplified method of RNA isolation termed Exclusion-Based Sample Preparation (ESP).71 patient samples with VLs ranging from <40 to >3,000,000 copies/mL were used to compare the two methods. We demonstrated equivalent LOD (~50 copies/mL) and high accuracy (average difference between methods of 0.08 log, R2 = 0.97). Using expenditures from this trial, we estimate that the cost of the reagents and consumables for this assay to be approximately $5 USD. As cost is a significant barrier to implementation of VL testing, we anticipate that our assay will enhance access to this critical monitoring test in developing countries.

Optimal timing for elective egg freezing

OBJECTIVE

To estimate the optimal age to pursue elective oocyte cryopreservation.

DESIGN

A decision-tree model was constructed to determine the success and cost-effectiveness of oocyte preservation versus no action when considered at ages 25-40 years, assuming an attempt at procreation 3, 5, or 7 years after initial decision.

SETTING

Not applicable.

PATIENT(S)

Hypothetical patients 25-40 years old presenting to discuss elective oocyte cryopreservation.

INTERVENTION(S)

Decision to cryopreserve oocytes from age 25 years to age 40 years versus taking no action.

MAIN OUTCOME AND MEASURE(S)

Probability of live birth after initial decision whether or not to cryopreserve oocytes.

RESULT(S)

Oocyte cryopreservation provided the greatest improvement in probability of live birth compared with no action (51.6% vs. 21.9%) when performed at age 37 years. The highest probability of live birth was seen when oocyte cryopreservation was performed at ages <34 years (>74%), although little benefit over no action was seen at ages 25-30 years (2.6%-7.1% increase). Oocyte cryopreservation was most cost-effective at age 37 years, at $28,759 per each additional live birth in the oocyte cryopreservation group. When the probability of marriage was included, oocyte cryopreservation resulted in little improvement in live birth rates.

CONCLUSION(S)

Oocyte cryopreservation can be of great benefit to specific women and has the highest chance of success when performed at an earlier age. At age 37 years, oocyte cryopreservation has the largest benefit over no action and is most cost-effective.

The role of diagnostic tissue in research

There are two broad classes (or categories) of excised human tissue: diagnostic tissue (DT) and research tissue (RT). Classification of excised human tissue does not define its ultimate use and ultimate use of excised human tissue does not define its classification. While both DT and RT can be used for research, DT has specific requirements with respect to how it must be handled if and when being accessed for research. We highlight distinguishing features of DT: (1) it is a clinical record, (2) it must be identifiable to a specific individual, (3) it is stewarded by pathology departments/clinical laboratories and (4) it has a mandatory retention period. We discuss how the further sub-classification of DT into archived DT (aDT) and excess DT (eDT) impacts the nature of its role in research. We examine the concept of DT as a clinical record and emphasize the impact of mandatory retention as it applies to how DT may be accessed for research purposes. We explain the role of post-retention eDT as a source of RT as well as procedures for access to in-retention aDT for research. Clarity of such issues will facilitate responsible access to DT for research.

Dried-blood spots: a cost-effective field method for the detection of Chikungunya virus circulation in remote areas

BACKGROUND

In 2005, there were outbreaks of febrile polyarthritis due to Chikungunya virus (CHIKV) in the Comoros Islands. CHIKV then spread to other islands in the Indian Ocean: La Réunion, Mauritius, Seychelles and Madagascar. These outbreaks revealed the lack of surveillance and preparedness of Madagascar and other countries. Thus, it was decided in 2007 to establish a syndrome-based surveillance network to monitor dengue-like illness.

OBJECTIVE

This study aims to evaluate the use of capillary blood samples blotted on filter papers for molecular diagnosis of CHIKV infection. Venous blood samples can be difficult to obtain and the shipment of serum in appropriate temperature conditions is too costly for most developing countries.

METHODOLOGY AND PRINCIPAL FINDINGS

Venous blood and dried-blood blotted on filter paper (DBFP) were collected during the last CHIKV outbreak in Madagascar (2010) and as part of our routine surveillance of dengue-like illness. All samples were tested by real-time RT-PCR and results with serum and DBFP samples were compared for each patient. The sensitivity and specificity of tests performed with DBFP, relative to those with venous samples (defined as 100%) were 93.1% (95% CI:[84.7-97.7]) and 94.4% (95% CI:[88.3-97.7]), respectively. The Kappa coefficient 0.87 (95% CI:[0.80-0.94]) was excellent.

CONCLUSION

This study shows that DBFP specimens can be used as a cost-effective alternative sampling method for the surveillance and monitoring of CHIKV circulation and emergence in developing countries, and probably also for other arboviruses. The loss of sensitivity is insignificant and involved a very small number of patients, all with low viral loads. Whether viruses can be isolated from dried blood spots remains to be determined.

Specimen pooling for efficient use of biospecimens in studies of time to a common event

For case-control studies that rely on expensive assays for biomarkers, specimen pooling offers a cost-effective and efficient way to estimate individual-level odds ratios. Pooling helps to conserve irreplaceable biospecimens for the future, mitigates limit-of-detection problems, and enables inclusion of individuals who have limited available volumes of biospecimen. Pooling can also allow the study of a panel of biomarkers under a fixed assay budget. Here, we extend this method for application to discrete-time survival studies. Assuming a proportional odds logistic model for risk of a common outcome, we propose a design strategy that forms pooling sets within those experiencing the outcome at the same event time. We show that the proposed design enables a cost-effective analysis to assess the association of a biomarker with the outcome. Because the standard likelihood is slightly misspecified for the proposed pooling strategy under a nonnull biomarker effect, the proposed approach produces slightly biased estimates of exposure odds ratios. We explore the extent of this bias via simulations and illustrate the method by revisiting a data set relating polychlorinated biphenyls and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene to time to pregnancy.

Psychiatric brain collection in Macedonia: general lessons for scientific collaboration among countries of differing wealth

Macedonia is a small country, and the current state has been independent for only 22 years. Medical research, which requires an extensive infrastructure, has been limited. We describe our experience in developing Macedonian research through a mutually beneficial collaboration between institutions in Macedonia and the United States.

[Evaluation of a UF-1000i screening method to identify the bacteriuria for cultures and susceptibility testing]

Urine culture remains the gold standard for diagnosing urinary tract infections, but most clinical samples yield negative results. Fast screening methods will improve the turnaround time and also reduce the associated costs. We evaluated the detection of bacteria using the Sysmex UF-1000i urine analyzer to identify negative samples which do not need further culture testings. The bacterial counts of the UF-1000i method and of the conventional culture of 197 samples, including 117 samples of midstream urine (MU) and 80 from catheter ports (CU), were prospectively compared, and the patient backgrounds were reviewed. The cut-off values to determine the necessity for culture were 2.7 bacteria/microL for MU and 11.0 bacteria/microL for CU samples, and 16.2% of the MU and 30.0% of the CU samples did not require cultures. These cut-off values are similar to those described in previous studies, however, our findings suggest that it would therefore be possible to reduce the need for unnecessary samples by the use of our cut-off values, which utilize the CU and MU samples separately. The cost reduction was calculated to be $239-306 per 100 samples. This UF-1000i screening method is an acceptable modality which improves the turnaround time, workload and cost to perform urine cultures.

Saving resources: avian influenza surveillance using pooled swab samples and reduced reaction volumes in real-time RT-PCR

The occurrence of highly pathogenic (HP) avian influenza (AI) H5N1 in Asia and its spread to Africa and Europe prompted costly monitoring programs of wild birds and domestic poultry. AI virus excretion is tested by examining avian swab samples by real-time reverse transcription PCR (RT-qPCR). In this study, pools of swab samples and a reagents volume reduction per RT-qPCR were evaluated as measures of economization. Viral transport medium and faecal matrices were spiked with different low pathogenic AI virus strains and tested for loss of target RNA during all processing steps as individual rayon swabs or in sample pools of 5, 10 and 15 swabs. Fresh faeces from Mallard ducks and other aquatic bird species as sample matrix resulted in loss of AIV RNA of about 90% compared to transport medium. Due to sample RNA dilution in pools the likelihood of detection of single positive samples is decreasing with increasing size of sample pools. However, pools of five samples containing only one positive sample consistently gave positive results. Similarly, no differences in detection rates were obtained when analyzing 1030 wild bird swab samples either individually or in pools of five. Reducing the reaction volume of influenza A virus generic as well as of subtype-specific RT-qPCRs to 12.5 μl (2.5 μl template) instead of 25 μl did not adversely affect the limit of detection of these RT-qPCRs. A significant economic benefit without impeding detection efficacy can be achieved when sample pools of five samples are analyzed by RT-qPCR using a reduction of the reaction mix to the half of the original volume.

A comparison of molecular methods for hepatitis B virus (HBV) DNA detection from oral fluid samples

The objective of the present study was to evaluate four commercial DNA extraction methods and three PCR protocols for hepatitis B virus (HBV) detection in artificially contaminated oral fluid samples. The extraction protocols were selected based on ease of use and cost, and were also compared with respect to sensitivity and cost. Prior PCR optimization was conducted, in which the sample volume for DNA extraction and the concentrations of DNA and Taq DNA polymerase in the PCR were adjusted. One-round PCR, used to amplify the core region of the HBV genome, achieved high levels of sensitivity in comparison with nested and semi-nested PCR experiments that were designed for the amplification of HBV surface protein genes. Of the four extraction protocols evaluated, the RTP DNA/RNA Virus Mini kit and the QIAamp DNA Mini kit gave the highest recovery rates, presenting 20 copies of HBV DNA ml(-1) as the limit of detection. These results suggest that HBV DNA can be detected from oral fluid samples but that the optimization of the PCR assays and the choice of extraction methods must be determined by laboratories before the implementation of this method in routine diagnostics.

Experimental use of two standard tick collection methods to evaluate the relative effectiveness of several plant-derived and synthetic repellents against Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae)

We used two standard tick collection methods to test the relative effectiveness of two natural product compounds (nootkatone and carvacrol, classified as an eremophilene sesquiterpene and a monoterpene, respectively, that are derived from botanical sources) with commercially-available plant-derived (EcoSMART Organic Insect Repellent, comprised of plant essential oils) and permethrin-based (Repel Permanone) repellents against Ixodes scapularis Say and Amblyomma americanum (L.). Cloth drags were equally effective in sampling both species of host-seeking nymphs, whereas CO, traps attracted primarily A. americanum. All four repellents performed well on drags, with nootkatone and Permanone Repel (100% repelled through 14 d) slightly more effective than carvacrol and EcoSMART (90.7% and 97.7% repelled at 14 d, respectively) at repelling I. scapularis nymphs. Although the same trend in percent repellency was noted in the CO2 trap trial against both A. americanum nymphs and adults, EcoSMART outperformed Permanone in repelling A. Americanum nymphs after 14 d in the drag trial. Generally, the effectiveness of all repellents tested declined over time. The use of tick drags and CO2 traps was rapid, inexpensive, and easy to use in determining the relative effectiveness of repellents in the field.

Characterizing populations of individuals using pooled samples

Biomonitoring involves the assessment of human or animal populations by measuring organic or biological compounds or their metabolites in the body fluids or tissues of individuals in those populations. Pooling samples before making analytical measurements can reduce the costs of biomonitoring by reducing the number of analyses. By proper choice of pooled-sample design, population means can be estimated without measuring individual samples. I present a statistical method for characterizing an entire population distribution of such compounds by exploiting the theoretic relationship between interindividual-sample variance and the variation between pooled samples. I use simulation experiments to determine an optimum pooled-sample design as a function of the number of subpopulations and the number of available samples. Using pooled samples to characterize populations is not only more cost-efficient, but also in some cases it can lead to more precise and less biased parameter estimation than that occurs with individual samples.

Simple practical approach for sample loading prior to DNA extraction using a silica monolith in a microfluidic device

A novel DNA loading methodology is presented for performing DNA extraction on a microfluidic system. DNA in a chaotropic salt solution was manually loaded onto a silica monolith orthogonal to the subsequent flow of wash and elution solutions. DNA was successfully extracted from buccal swabs using electro-osmotic pumping (EOP) coupled with in situ reagents contained within a 1.5% agarose gel matrix. The extracted DNA was of sufficient quantity and purity for polymerase chain reaction (PCR) amplification.

Assessment of sample collection and storage methods for multicenter immunologic research in children

Multicenter studies involving both large and small centers separated by significant distances pose unique challenges to biological sample collection. The objective of this study was to evaluate protocols for determining inflammatory biomarkers that are cost and manpower efficient for handling blood destined for a sample repository. Tempus (Applied Biosystems) and Paxgene (Qiagen) blood collection systems were evaluated for RNA isolation. P100 tubes (BD), containing propriety stabilizers for preservation of plasma proteins, were evaluated for protein content and compared with plasma collected in conventional tubes. Blood for plasma separation was spiked with recombinant TNF-alpha and IL-2 prior to being processed and stored under various conditions. The Tempus RNA system produced a significantly greater yield of RNA at comparable quality when stored at 4 degrees C and shipped at ambient temperature than any other condition tested. The Tempus system was 20% less expensive and required approximately 40% less processing time thereby reducing costs. The P100 system preserved recombinant TNF-alpha in blood shipped at ambient temperature significantly better than conventionally collected plasma that was shipped on dry ice. There was no significant difference in IL-2 levels between the two collection methods and shipping temperatures. The Tempus RNA blood collection tubes and the P100 protein stabilization system provide the opportunity for reliable collection and ambient temperature transport of samples in multicenter studies. This cost-effective, standardized protocol for a large multicenter trial ensures the integrity of biological samples and maximizes study participation by both large and small centers.

[Nonspecific clinical signs in pigs and use of exclusion diagnosis for classical swine fever: a survey among pig farmers and veterinary practitioners]

Outbreaks of Classical Swine Fever (CSF) occurred in spring 2006 in Germany close to the Dutch border. On 6th April Dutch pig farmers were given the possibility to submit blood samples directly via their veterinary practitioner to the National Reference Laboratory for CSF if their pigs had non-specific clinical symptoms or if pigs were being treated with antibiotics. The pig farm was not quarantined and was not visited by the veterinary authorities. Over a period of 9 weeks 156 pig farmers submitted whole blood samples via 50 different veterinary practices. All samples tested negative in the PCR test. These pig farmers and veterinary practitioners were asked to respond to a postal questionnaire with questions regarding their experience with this new diagnostic possibility, the distribution of the costs involved, a comparison with other instruments, such as official notification or use of a leukocyte count test, and their knowledge of clinical signs of CSF. 65 pig farmers (42%) and 33 veterinary practices (66%) returned the questionnaire. The main results indicated that pig farmers (72%) would use this type of exclusion diagnostics sooner than that they would approach the veterinary authorities (practitioners: 86%). Moreover the respondents considered the fact that the farm was not quarantined immediately to be an advantage (pig farmers, 79%; practitioners, 88%). 32 percent of the pig farmers were not aware that they were required to submit blood samples if pigs were being treated with antibiotics (practitioners: 11%). The majority of pig farmers and practitioners were not satisfied with the current distribution of the costs involved: in their opinion the costs of the PCR test, the costs of the veterinary practitioner and the costs for shipping the samples to the reference laboratory should be paid out of the Animal Health Fund (50% government and 50% industry) or by the government. If the current distribution of the costs is not changed, a large proportion of the pig farmers indicated that they would not use this form of exclusion diagnostics for CSF in the future. Pig farmers appeared to have a rather limited knowledge of the clinical signs of CSF: 33% of the pig farmers could mention maximally three clinical signs of CSF, and 7% could not mention a single clinical sign of CSF and said they were entirely dependent on the practitioners' ability to judge a CSF-suspect situation.

[Pneumatic tube net conveying systems in the hospital environment]

The primary aim for having recourse to a pneumatic tube net to convey blood samples, is to shorten the turn around time in which transport delay is the major issue: this represents the logical answer to this question, as opposed to point of care testing. It also permits saving in transport personnel. It is of the highest importance of having recourse only to a high quality equipment (robust, reliable) likely to face the heavy workload occurring in a hospital environment, avoiding the use of light structures primarily designed for cash remittance. Implanting such a net in newly constructed structures is generally easy, while connecting the net into old buildings might meet some space limiting difficulties. Detailed prior planning of the network is a major issue for success.

Training program on microbiological test collection material methods at a teaching hospital: investment and result assessment

This study aimed at evaluating the results, direct costs and investment of a training program on microbiological test material collection at a teaching hospital. Test collections that did not follow the established criteria (failure) were considered as the result measure. Variable and absorption costing were used to calculate direct costs and investments, respectively. Of the 11,893 collected materials, failures were evidenced in 59 (0.5%). Direct cost corresponded to R$ 154.10 and R$ 2,431.29 was invested in training. These findings revealed that the evidenced number of anomalies (failures) represented a low percentage in relation to the total collected material for microbiological exams. Therefore, this should not be considered a critical point that justifies the continuity of the training and, consequently, the investment.

Estimating the cost-effectiveness of quality-improving interventions in oral anticoagulation management within general practice

OBJECTIVES

A clinical trial, "Belgian Improvement Study on Oral Anticoagulation Therapy (BISOAT)," significantly improved the quality after implementing four different quality-improving interventions in four randomly divided groups of general practitioners (GPs). The quality-improving interventions consisted of multifaceted education with or without feedback reports on their performance, international normalized ratio (INR) testing by the GP with a CoaguChek device or computer-assisted advice for adapting oral anticoagulation therapy. The quality improvement in INR control versus baseline was similar in the four groups. The aim of the current study was to calculate the cost-effectiveness and influencing factors of the four quality-improving interventions compared with usual care.

METHODS

Activity-based costing techniques with questionnaires were used to determine the global costs per patient per month in the different intervention groups. Effectiveness data were obtained from the BISOAT study. Cost-effectiveness was expressed as cost per additional day within a 0.5 range from INR target.

RESULTS

The one-time cost of multifaceted education was 49,997 euro for the whole study. Monthly continuous costs per intervention ranged between 37 euro and 54 euro per patient. Using the CoaguChek in combination with the multifaceted education was associated with net savings and quality improvement, hence dominated usual care. Sensitivity analyses showed improved cost-effectiveness with extended duration and with increased program size.

CONCLUSION

Implementation of the combination multifaceted education with the use of the CoaguChek is a cost-effective new organizational model of oral anticoagulation management in general practice.

Long-term storage and recovery of buccal cell DNA from treated cards

Economical methods for collecting and storing high-quality DNA are needed for large population-based molecular epidemiology studies. Buccal cell DNA collected via saliva and stored on treated filter paper cards could be an attractive method, but modest DNA yields and the potential for reduced recovery of DNA over time were unresolved impediments. Consequently, buccal cell DNA collection via oral mouthwash rinsing became the method of choice in epidemiologic studies. However, the amount of genomic DNA (gDNA) required for genotyping continues to decrease, and reliable whole genome amplification (WGA) methods further reduced the mass of gDNA needed for WGA to 10 ng, diminishing the obstacle of low DNA yields from cards. However, concerns about yield and DNA quality over time remained. We located and analyzed 42 buccal cell saliva samples collected and stored on treated cards for 7 years at room temperature, -20 degrees C, and -80 degrees C. We recovered DNA from the treated cards, estimated the concentration by a human-specific quantitative real-time PCR assay, and evaluated the quality by PCR amplification of 268-, 536-, and 989-bp fragments of the beta-globin gene and by AmpFlSTR Identifiler assay analysis. Most DNA yields per 3-mm punch were <10 ng, and most PCR amplicons failed to amplify, where size of the amplicon was negatively associated with successful amplification. Using these methods, treated cards did not consistently provide sufficient quantities of buccal cell gDNA after 7 years of storage for genotyping or WGA.

Partner notification of chlamydia infection in primary care: randomised controlled trial and analysis of resource use

OBJECTIVE

To evaluate the effectiveness of a practice nurse led strategy to improve the notification and treatment of partners of people with chlamydia infection.

DESIGN

Randomised controlled trial.

SETTING

27 general practices in the Bristol and Birmingham areas.

PARTICIPANTS

140 men and women with chlamydia (index cases) diagnosed by screening of a home collected urine sample or vulval swab specimen.

INTERVENTIONS

Partner notification at the general practice immediately after diagnosis by trained practice nurses, with telephone follow up by a health adviser; or referral to a specialist health adviser at a genitourinary medicine clinic.

MAIN OUTCOME MEASURES

Primary outcome was the proportion of index cases with at least one treated sexual partner. Specified secondary outcomes included the number of sexual contacts elicited during a sexual history, positive test result for chlamydia six weeks after treatment, and the cost of each strategy in 2003 sterling prices.

RESULTS

65.3% (47/72) of participants receiving practice nurse led partner notification had at least one partner treated compared with 52.9% (39/68) of those referred to a genitourinary medicine clinic (risk difference 12.4%, 95% confidence interval -1.8% to 26.5%). Of 68 participants referred to the clinic, 21 (31%) did not attend. The costs per index case were 32.55 pounds sterling for the practice nurse led strategy and 32.62 pounds sterling for the specialist referral strategy.

CONCLUSION

Practice based partner notification by trained nurses with telephone follow up by health advisers is at least as effective as referral to a specialist health adviser at a genitourinary medicine clinic, and costs the same. Trial registration Clinical trials: NCT00112255.

Constraints on transportation of reagents, reference materials and samples, difficulties and possible solutions: a user's perspective

The air transportation of infectious materials is regulated by international air transport associations and based on United Nations Model regulations which have become more practical in addressing animal disease agents. However, individual countries' import and interstate requirements determine what materials can be imported and transported, and this approval process can be long, resulting in delays in organism confirmation, use of international OIE and other reference laboratories, and acquisition of reference materials, proficiency test panels, and reagents for performing necessary testing. Delays can be prevented for permits that are required for the routine work performed by a laboratory through the use of comprehensive and annually renewed permits. This process, however, does not address new and exotic agents where time is critical to an effective emergency response. This paper suggests actions by both the OIE and regulatory authorities which can assist in streamlining and expediting the permit process.

Obtaining urine for culture from non-potty-trained children

The accurate diagnosis of urinary tract infection (UTI) in young children is important for initial management and the prevention of long-term damage to the developing kidney. Various methods are used for urine collection from the non-potty-trained age group, including catheterisation, suprapubic aspiration, clean-catch sampling, adhesive bag sampling and urine collection pads. Research literature was examined to identify which method is most effective. The themes that evolved from the review were parents' and nurses' views on ease of use, reliability of sample obtained and cost-effectiveness. Although not the most convenient method, clean-catch gives more reliable results making it also the most cost effective approach. Change management strategies are required to overcome barriers to research implementation and to ensure best practice.

A comparison of three stool tests for colorectal cancer screening

The annual guaiac or immunochemical fecal occult blood test (FOBT) is one of the five colorectal cancer (CRC) screening regimens recommended by the American Cancer Society (Smith, Cokkinides, & Eyre, 2005). Stool-based deoxyribonucleic acid (DNA) testing for CRC is considered a promising technology (Smith, Cokkinides, & Eyre, 2003). Numerous features of three noninvasive stool tests for CRC are compared.

[Ligase chain reaction testing of pooled urine specimens to diagnose Chlamydia trachomatis infection]

OBJECTIVE

The purpose of this study was to assess the utility and validity of pooling urine samples for molecular diagnosis of Chlamydia trachomatis infection.

MATERIAL AND METHODS

Of 1,220 urine samples collected from Mexican female and male adolescents, 305 pools were composed of fourth individual samples each, based on a calculation of optimal pool size. These were processed by ligase chain reaction (LCR) for the detection of C. trachomatis. Positive and gray-zone pools were reanalyzed individually. Cost savings were calculated comparing actual costs of testing to the cost that would have been incurred testing all 1,220 samples individually.

RESULTS

Pools results were: 56 positive, 19 gray-zones and 230 negative. Following individual retesting of positive and gray-zone pools, 59 cases of C. trachomatis infection were identified (4.8% prevalence). Thus, a total of 601 LCR tests were performed, for a 50.4% savings considering only the direct cost of the test.

CONCLUSIONS

Our experience shows that sample pooling is both a reliable and convenient tool for CT surveillance in our setting. It should be considered in other similar settings where limited resources constraint surveillance of STIs.

Urine cytology: appropriate usage maximizes sensitivity and reduces cost

OBJECTIVE

Urine cytology is costly because of the skilled manpower required for analysis. Inappropriate requests are a significant drain both financially and on the cytopathologist's time. The present study aimed at identifying the extent and cause of this misuse and reduce it.

METHODS

An audit of urine cytology usage was undertaken using the hospital results reporting system to identify requests. Patient case notes were then obtained to gain further clinical information. Initially a 2-week period was analysed, following which departmental guidelines for requesting urine cytology were produced and circulated. The audit loop was then closed.

RESULTS

Over the initial 2-week period, 117 urine cytology requests were received. Thirty-three per cent were inappropriate, either because they were from patients with benign disease or because of duplication. Following the education programme this number fell to 6%. Expenditure on unnecessary samples thus decreased from pounds 2418 to only pounds 310, giving an annual overall saving of pounds 55,000.

CONCLUSION

Significant cost and time savings can be made if urine cytology is sent appropriately. Simple guidelines and staff education are the key to reducing inefficiency. Our findings have implications not just for cytopathology costs but for laboratory and radiology requests in general.