Cost-effective Laboratory Research Articles

The cost effectiveness of antiretroviral treatment strategies in resource-limited settings

Optimal resource allocation for antiretroviral treatment (ART) in developing countries requires assessment of different strategies for drug treatment and laboratory monitoring. To compare costs and outcomes for 10 000 simulated HIV-infected patients followed every 6 months for 10 years in a limited-resource setting. Five nested strategies, with and without the availability of a second-line treatment regimen, were simulated: (a) no ART (NO ART); (b) with ART but without any laboratory markers of HIV other than positive serology (ART ONLY); (c) ART plus total lymphocyte count (TLC); (d) ART plus CD4 cell counts (CD4); and (e) ART plus CD4 cell count plus viral load measurement (VL). Baseline prices of CD4 cell count and viral load measurements were $5.00 and $25.00 per test, respectively. With no second-line treatment available, treating 10 000 patients with ART ONLY compared with NO ART would cost $14.49 million [95% confidence interval (CI), 14.45-14.52] and would generate an additional 23 060 quality-adjusted life years (QALYS) (95% CI, 22 770-23 360) for a median incremental cost effectiveness ratio (ICER) of $628/QALY. Median ICER values per QALY for CD4 and VL strategies are $238 and $16 139, respectively, when second-line treatment is unavailable. With second-line ART available, the corresponding median ICER values are $8636, and $14 670. In the absence of second-line ART, the CD4 strategy is a more cost-effective laboratory testing strategy for managing HIV infection than either TLC or VL. Availability of second-line ART plus CD4 cell count and/or viral load measurement would save additional lives, but at high incremental cost.

Neutrophil VCS Parameters Are Superior Indicators for Acute Infection

A reliable and cost-effective laboratory method for diagnosing early bacterial infection is needed. The purpose of this study is to compare the sensitivity and specificity of the mean neutrophil volume (MNV) and neutrophil volume distribution width (NDW) parameters with manual band counts, as well as absolute neutrophil count (ANC) and Creactive protein (CRP). We analyzed the clinical history and laboratory data from 242 adult patients with subsequent randomization into 3 groups: patients with no apparent clinical evidence of infection (group 1), localized infection (group 2), and severe infection (group 3). Total white blood cell counts, percentage of neutrophils, ANC, band counts, MNV, and NDW were progressively elevated from group 1 to group 3. There were good correlations between MNV and ANC (P < .05) or band counts (P < .001). Similarly, the NDW correlated well with ANC (P < .001) and band counts (P < .05). Statistical analyses further confirmed that the MNV and NDW were better parameters, with larger areas under the curve than those of CRP, band count, and ANC. The neutrophil VCS parameters, MNV and NDW, have superior sensitivity and specificity compared to manual band count, ANC, and CRP. MNV and NDW are useful indicators in diagnosing acute infectious processes.

Autoimmune Hearing Loss: Improving Diagnostic Performance

Due to the lack of specific serological markers for the diagnosis of immune-mediated hearing loss, an exhaustive immunologic work-up study for patients is usually performed. The aim of the present study is to find the most cost-effective laboratory tests used for the diagnosis of this entity. Comparative study between 2 groups of patients with a high suspicion of suffering diverse clinical forms of immune-mediated hearing loss, subjected to different serologic testing designs: the classical immunologic work-up study (125 patients) in comparison with a more restricted examination analysis (57 patients), based on a high risk profile recently reported. Diagnostic efficiency was similar. Since financial resources are limited, ANA and immunophenotype of PBL (peripheral blood lymphocytes) are recommended for the evaluation of a patient with suspected immune-mediated hearing loss.

Simultaneous detection of enteropathogenic viruses in buffalos faeces using multiplex reverse transcription-polymerase chain reaction (mRT-PCR)

A multiplex reverse transcription- polymerase chain reaction (mRT-PCR) assay that detects Bovine Viral Diarrhoea Virus, Bovine Coronavirus, and Group A Rotaviruses in infected cell-culture fluids and clinical faecal samples is described. One hundred twenty faecal samples from buffalo calves with acute gastroenteritis were tested. The mRT-PCR was validated against simplex RT-PCR with published primers for Pestivirus, Coronavirus and Rotavirus. The multiplex RT-PCR was equally sensitive and specific in detecting viral infections compared with simplex RT-PCR. The mRT-PCR readily identified viruses by discriminating the size of their amplified gene products. This mRT-PCR may be a sensitive and rapid assay for surveillance of buffalo enteric viruses in field specimens. This novel multiplex RT-PCR is an attractive technique for the rapid, specific, and cost-effective laboratory diagnosis of acute gastroenteritis.

The Single-Step Multiplex Reverse Transcription- Polymerase Chain Reaction Assay for Detecting H5 and H7 Avian Influenza A Viruses

Avian influenza (AI) A virus subtypes H5 and H7 cause severe disease in domestic poultry, including chickens and turkeys. Moreover, H5 and H7 AI A viruses can cross the species barrier from poultry to humans. In the present study, we have developed a single-step multiplex reverse transcription-polymerase chain reaction assay (RT-PCR) for detecting H5 and H7 AI A viruses. This assay was applied to the poultry isolates with the aim of establishing a surveillance method to monitor possible transmission to humans. Two subtype-specific primer sets capable of producing PCR products of 157 and 326 base pairs corresponding to AI A virus H5 and H7 subtypes, respectively, were utilized in a one-step and one-tube reaction. The single-step multiplex RT-PCR assay developed in this study was found to be specific for detecting H5 and H7 AI A viruses. No specific amplification bands were detected with total nucleic acids extracted from other influenza hemagglutinin subtypes and other viral pathogens. The sensitivity of this assay was about 10(3) RNA copies/microl. In conclusion, this novel single-step multiplex RT-PCR is a simple assay with high potential for rapid, specific and cost effective laboratory diagnosis of H5 and H7 AI A virus isolates from clinical specimens of poultry.

The management of secondary osteoporosis

Secondary osteoporosis is common among patients being evaluated for osteoporosis. All men and premenopausal women with unexplained bone loss or a history of a fragility fracture should undergo a work-up for secondary osteoporosis. Also, postmenopausal women with risk factors for secondary osteoporosis should be carefully evaluated. The evaluation should include a thorough history, physical examination, bone mineral density testing, and laboratory testing. While there is no consensus for a cost-effective laboratory evaluation, some recommendations include: 25-hydroxyvitamin D, parathyroid hormone (PTH), serum and urine calcium, phosphate, creatinine, liver function tests, a complete blood count, testosterone in men, and thyroid-stimulating hormone. After a thorough review of the evaluation for secondary osteoporosis, this chapter reviews the pathophysiology and treatment of secondary osteoporotic disorders, including vitamin D insufficiency, osteomalacia, the osteoporosis of erosive inflammatory arthritis, ankylosing spondylitis, systemic lupus erythematosus, and osteoporosis related to anti-androgenic therapy for prostate cancer and aromatase inhibitor therapy for breast cancer. Physicians have a significant responsibility to evaluate and treat the underlying medical problem that is the cause of secondary osteoporosis and to optimize bone health in the individual patient.

T25 Repeat in the 3′ Untranslated Region of the CASP2 Gene: A Sensitive and Specific Marker for Microsatellite Instability in Colorectal Cancer

DNA mismatch repair deficiency is observed in about 10% to 15% of all colorectal carcinomas and in up to 90% of hereditary nonpolyposis colorectal cancer (HNPCC) patients. Tumors with mismatch repair defects acquire mutations in short repetitive DNA sequences, a phenomenon termed high-level microsatellite instability (MSI-H). The diagnosis of MSI-H in colon cancer is of increasing relevance, because MSI-H is an independent prognostic factor in colorectal cancer, seems to influence the efficacy of adjuvant chemotherapy, and is the most important molecular screening tool to identify HNPCC patients. To make MSI typing feasible for the routine pathology laboratory, highly reproducible and cost effective laboratory tests are required. Here, we describe a novel T25 mononucleotide marker in the 3'untranslated region of the CASP2 gene (CAT25) that displayed a quasimonomorphic repeat pattern in normal tissue of 200 unrelated individuals of Caucasian origin. In addition, CAT25 was monomorphic also in all tested donors of African and Asian origin (n = 102 and n = 79, respectively) and thus differs from the most commonly used markers BAT25 and BAT26. Without the analysis of corresponding normal tissue, CAT25 correctly detected 56 of 57 colorectal cancer specimens classified as MSI-H by using the standard National Cancer Institute/International Collaborative Group-HNPCC marker panel. Combined with the standard markers BAT25 and BAT26 in a multiplex PCR, all MSI-H colorectal cancer samples were typed correctly. No false-positive results were obtained in 60 non-MSI-H control colorectal cancer specimens. These data suggest that CAT25 should be included into novel marker panels for microsatellite testing thus allowing for a significant reduction of the complexity and costs of MSI typing. Moreover, CAT25 represents a highly promising marker for early detection of colorectal cancer in HNPCC germ line mutation carriers.

Signal-Boosted Qualitative Ultrasensitive p24 Antigen Assay for Diagnosis of Subtype C HIV-1 Infection in Infants Under the Age of 2 Years

The gold standard for diagnosis of HIV-1 infection in infants under the age of 2 years is DNA or reverse transcriptase polymerase chain reaction. However, these tests are expensive and therefore not available in resource-limited countries. With the increasing availability of antiretroviral drugs for prevention of mother-to-child transmission of HIV and treatment of AIDS in resource-poor countries, there is an urgent need to develop cheaper, alternative, and cost-effective laboratory methods for early diagnosis of infant HIV-1 infection that will be useful in identifying infected infants who may benefit from early cotrimoxazole prophylaxis or commencement of antiretroviral therapy. We evaluated an alternative method, the enzyme-linked immunosorbent assay-based qualitative ultrasensitive p24 antigen assay for diagnosis of subtype C HIV-1 infection in infants under the age of 2 years using DNA polymerase chain reaction as the reference method. The assay showed a sensitivity of 96.7% (95% CI: 93.0-100) for detection of HIV-1 infection among infants 0-18 months of age with a specificity of 96.1% (95% CI: 91.7-100). These evaluated parameters were not statistically different between infants aged 0-6 and 7-18 months. The ultrasensitive p24 antigen assay is a useful diagnostic test for detection of HIV-1 infection among infants aged 0-18 months.

A novel RT-multiplex PCR for enteroviruses, hepatitis A and E viruses and influenza A virus among infants and children with diarrhea in Vietnam

A novel reverse transcription-multiplex polymerase chain reaction (RT-multiplex PCR) assay that can detect enteroviruses, hepatitis A and E viruses and influenza A virus from various hosts (avian species, human, swine and horse) was developed. The identification of that group of viruses was performed with the mixture of four pairs of published specific primers (F1 and R1, P3 and P4, 2s and 2as, MMU42 and MMU43) for amplifying viral genomes and specifically generated four different amplicon sizes of 440, 267, 146 and 219 bp for enteroviruses, hepatitis A and E viruses and influenza A virus, respectively. A total of 276 fecal specimens (previously screened for rotavirus, adenovirus, norovirus, sapovirus and astrovirus-negative) from infants and children admitted into hospital with acute gastroenteritis in Ho Chi Minh city, Vietnam during October 2002 and September 2003 were collected and further tested for the presence of those viruses by RT-multiplex PCR. Enteroviruses were identified in 27 specimens and this represented 9.8%. No hepatitis A and E viruses and influenza A virus was found among these subjects. The sensitivity and specificity of RT-multiplex PCR were also assessed and demonstrated the strong validation against RT-monoplex PCR. Taken together, the findings clearly indicated that this novel RT-multiplex PCR is a simple and potential assay for rapid, sensitive, specific and cost-effective laboratory diagnosis to investigate molecular epidemiology of acute gastroenteritis caused by enteroviruses, hepatitis A and E viruses and influenza A virus. This report is the first, to our knowledge, detecting these kinds of viruses in diarrheal feces from infants and children in Vietnam.

T lymphocytes among HIV-infected and -uninfected infants: CD4/CD8 ratio as a potential tool in diagnosis of infection in infants under the age of 2 years

BackgroundSerologic tests for HIV infection in infants less than 18 months do not differentiate exposure and infection since maternally acquired IgG antibodies may be detected in infants. Thus, the gold standard for diagnosis of HIV-1 infection in infants under the age of 2 years is DNA or reverse transcriptase polymerase chain reaction. There is an urgent need to evaluate alternative and cost effective laboratory methods for early diagnosis of infant HIV-1 infection as well as identifying infected infants who may benefit from cotrimoxazole prophylaxis and/or initiation of highly active antiretroviral therapy.MethodsWhole blood was collected in EDTA from 137 infants aged 0 to 18 months. DNA polymerase chain reaction was used as the reference standard for diagnosis of HIV-1 infection. T-cell subset profiles were determined by flow cytometry.ResultsSeventy-six infants were DNA PCR positive while 61 were negative. The median CD4 counts of PCR negative infants were significantly higher than those of the PCR positive infants, p < 0.001. The median CD4/CD8 ratio and the %CD4 of the PCR positive infants were both significantly lower than those of the negative infants, p < 0.001. The CD4/CD8 ratio had a >98% sensitivity for diagnosis of HIV-1 infection and a specificity of >98%.ConclusionThe CD4/CD8 ratio appears useful in identifying HIV-infected infants. The development of lower cost and more robust flow cytometric methods that provide both CD4/CD8 ratio and %CD4 may be cost-effective for HIV-1 diagnosis and identification of infants for cotrimoxazole prophylaxis and/or highly active antiretroviral therapy.

A simple and rapid method for labelling earthworms with 15N and 13C

A simple, rapid and cost-effective laboratory method was developed for labelling soil-feeding earthworms simultaneously with 15N and 13C. The method circumvents the production of labelled plant material and can be adapted to devise pulse-labelling or long-term labelling protocols. Soil was amended with 15NH 4 + and incubated for 7 days. Then, U- 13C-glucose was added and endogeic earthworms, Aporrectodea caliginosa (Oligochaeta: Lumbricidae), were provided individually with 4 g of this pre-incubated soil. The labelling period was 4 days. The labelling efficiency (percentage of tracer retained in earthworm tissues) was estimated to be 15.8% for 15N and 10.3% for 13C. The loss of 15N and 13C label from tissue and mucus was traced for 21 days post-labelling. Label loss from mucus was best described by a two-term exponential function, whereas the label loss in body tissue followed a single-term exponential function. Half-life estimates for the 15N and 13C tracers in body tissue were 16 and 37 days, respectively.

A simple and rapid single-step multiplex RT-PCR to detect Norovirus, Astrovirus and Adenovirus in clinical stool samples

A single-step multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay that detects and identifies Norovirus, Astrovirus and Adenovirus in clinical stool samples is described. Four hundred sixty stool samples were tested from patients with non-rotavirus acute gastroenteritis, that were either stored at −80 °C and tested retrospectively, or tested immediately after viral nucleic acid extraction in a prospective manner, including outbreaks of gastroenteritis that occurred in Germany during the winter of 2003. The multiplex RT-PCR was validated against simplex RT-PCR with published primers for Norovirus (JV12/JV13 and p289/p290) and Astrovirus (Mon340/348), and against simplex PCR for Adenovirus. In both retrospective and prospective settings, the multiplex RT-PCR was equally sensitive and specific in detecting non-rotavirus infections compared with simplex RT-PCR/PCR. The specificity of the multiplex RT-PCR was assessed by sequencing of the amplicons that showed high nucleotide identities to Norovirus genogroup I/1, I/4, II/2, or II/4 clades, as well as to Astrovirus serotypes 1, 2, 4, or 8. The multiplex RT-PCR was also more sensitive than Astrovirus and Norovirus antigen enzyme immunoassays (IDEIA, Dako), as well as Astrovirus isolation in cell culture. This novel multiplex RT-PCR is an attractive technique for the rapid, specific, and cost-effective laboratory diagnosis of non-rotavirus acute gastroenteritis.

Turbulent Boundary-Layer Simulation with an Array of Loudspeakers

The feasibility is discussed of simulating a random pressure field having the same spatial correlation function as a turbulent boundary-layer pressure field using an array of loudspeakers. This approach could provide a cost-effective laboratory method of measuring the boundary-layer noise transmitted through aircraft fuselage structures. Initially, a theoretical model is used to predict the vibroacoustic response of randomly excited panels. A method of generating a pressure field with predefined statistical properties using an array of loudspeakers is then introduced. Results are obtained in a typical test case for the simulation of boundary-layer-induced noise. It is shown how the number of loudspeakers required to achieve a reasonable approximation of the boundary-layer excitation scales with frequency. It is found that a coarse reproduction of the boundary-layer excitation, using a reduced set of loudspeakers, can still give a good approximation of the panel vibroacoustic response, thus suggesting that direct simulation of the panel response to a boundary-layer excitation using loudspeakers could be feasible.

A simple and rapid single-step multiplex RT-PCR to detect Norovirus, Astrovirus and Adenovirus in clinical stool samples

A single-step multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay that detects and identifies Norovirus, Astrovirus and Adenovirus in clinical stool samples is described. Four hundred sixty stool samples were tested from patients with non-rotavirus acute gastroenteritis, that were either stored at −80 °C and tested retrospectively, or tested immediately after viral nucleic acid extraction in a prospective manner, including outbreaks of gastroenteritis that occurred in Germany during the winter of 2003. The multiplex RT-PCR was validated against simplex RT-PCR with published primers for Norovirus (JV12/JV13 and p289/p290) and Astrovirus (Mon340/348), and against simplex PCR for Adenovirus. In both retrospective and prospective settings, the multiplex RT-PCR was equally sensitive and specific in detecting non-rotavirus infections compared with simplex RT-PCR/PCR. The specificity of the multiplex RT-PCR was assessed by sequencing of the amplicons that showed high nucleotide identities to Norovirus genogroup I/1, I/4, II/2, or II/4 clades, as well as to Astrovirus serotypes 1, 2, 4, or 8. The multiplex RT-PCR was also more sensitive than Astrovirus and Norovirus antigen enzyme immunoassays (IDEIA, Dako), as well as Astrovirus isolation in cell culture. This novel multiplex RT-PCR is an attractive technique for the rapid, specific, and cost-effective laboratory diagnosis of non-rotavirus acute gastroenteritis.

Chronic lymphocytic leukaemia: new biological markers for assessing prognosis.

Well-established clinical staging systems continue to form a basis for deciding when to initiate treatment and assigning prognosis in chronic lymphocytic leukaemia. However, these staging systems do not identify those patients with early-stage disease who will progress to require treatment. Recent developments have provided a variety of prognostic markers, which can determine those patients with poor prognosis disease. For example, serum markers (soluble CD23), cell surface (CD38) and cytoplasmic (ZAP70) proteins, cytogenetics and immunoglobulin gene mutational status have all been utilised for this purpose. In order for patients to benefit fully from these discoveries they need to be translated into rapid, standardised and cost-effective clinical laboratory tests. The current range of prognostic markers, and techniques for measuring them are discussed.

Clinical laboratory consultation: appropriateness to laboratory medicine

New and expensive treatments, introduction of difficult to interpret complex tests, a greater reliance on nurse practitioners as deliverers of primary care and patient initiated testing, all make it likely that in the future greater emphasis will be placed on appropriate use of cost-effective laboratory tests. The most promising solution to inappropriate utilization of laboratory services is a greater reliance on clinical laboratory consultants. At present, many laboratory physicians and scientists cannot compete with specialist physicians in terms of the ability to provide credible helpful advice on test selection and results interpretation. Educational prerequisites to effective consultation are: understanding of disease pathogenesis, knowledge of clinical problem solving and identification with clinical questions. The latter requires clinical experience or intensive training in clinical laboratory consultation. Further barriers to implementation of comprehensive laboratory consultation services include resistance on the part of practicing physicians, health care administrators and insurers. Whether these barriers can be overcome or not, the future will include comprehensive laboratory consultation services conducted through web-based access to advice on test selection and interpretation of results.

Diagnosis and Treatment of Rhinovirus Respiratory Infections

Acute upper viral respiratory infection (VRI) is the number one cause of illness for which patients seek medical care in the United States. Rhinoviruses, members of the family Picornaviridae, are the causative pathogens in more than half of VRIs, and they are associated with acute exacerbations of respiratory disease, including asthma, sinusitis, otitis media, and COPD. Owing to the lack of commercial availability of rapid and cost-effective laboratory tests to confirm the presence of VRI, the diagnosis is most commonly made empirically, based on patient history and physical examination. Currently, no antiviral agents that are active against picornaviruses are available for clinical use. Antimicrobial agents, frequently prescribed for VRIs, are not active against viruses, and their inappropriate and widespread use has contributed to an increase in antimicrobial resistance among bacteria commonly involved in respiratory tract infections. Several newer antiviral agents are being evaluated for treatment of VRIs. Although a variety of mechanisms and agents have been tested, few have shown significant clinical benefit in human trials. The most advanced antiviral agent in clinical trials is pleconaril, a novel viral capsid-binding inhibitor with potent and highly specific in vitro activity against the majority of serotypes of rhinoviruses and enteroviruses. Clinical trials of pleconaril for the treatment of VRIs have been conducted, and the role of pleconaril in patients with chronic lung disease is being evaluated.

Design, Build and Test of a Semi-Monocoque Wing Structure

A time and cost effective laboratory exercise has been developed to provide large numbers of students with practical hands-on experience of a complete structural development cycle in the first year of their M.Eng. Aeronautical Engineering course. Teams of students are given a set of requirements to design, build and test a small-scale semi-monocoque wing box and centre section structure within a strict schedule. The exercise is assessed by a competitive team component based on structural performance and individual component based on a certification report. The exercise is well received by the students and provides a useful practical experience to relate to other more academic parts of the materials, structures and design courses. The prescribed form, although not covering the conceptual stage of design, provides an instructive layout for students to visualize a complete structural development process clearly despite the inherently large number of problems to be considered and solved.

Compact disc players in the laboratory: experiments in optical storage, error correction, and optical fiber communication

The compact disc player is a synergy of optics, communication theory, digital signal processing, and control engineering. This familiar consumer product may be employed as a cost-effective laboratory instrument to teach the fundamentals of optical storage, error detection and correction, and optical communication. The compact disc audio system, from analog input, through optical storage and distribution, to audio reproduction, provides an excellent model of a complete real-world optical transmission and storage system. A series of experiments, which illustrate some of the more significant operational principles of the compact disc player, are presented in this contribution. Optical read-out and the physics of information density are explored through a set of experiments in optical storage. Error detection and correction are studied experimentally by evaluating the performance of the compact disc player's error control system. The design of an optical fiber communication system is studied by extracting the channel bit stream from a compact disc player, transmitting it over an optical fiber link, and then reinserting it back into the compact disc player for audio reproduction.

The Production of High-Purity Water in the Clinical Laboratory

As the sensitivity and variety of tests increase, the types and tolerable concentrations of impurities that may inhibit clinical tests become an increasing concern. Because water constitutes a high percentage of the buffers and reaction mixtures used in clinical assays, the use of high-purity water is critical for reliable, consistent, and cost-effective laboratory analysis. A wide range of contaminants exists in potable water supplies and must be removed with a water system containing the proper combination of specific purification technologies. Technologies such as activated carbon, reverse osmosis, ion exchange, and distillation have particular purification capabilities and must be selected based on their ability to consistently produce water with purity suitable for specific test methods. The National Committee for Clinical Laboratory Standards (NCCLS) provides guidelines for the production and use of purified water in the laboratory. The production of reagent water that meets the NCCLS guidelines requires proper measurement and monitoring of contaminant levels in both incoming source water and product reagent water. The introduction of new diagnostic tests requires the removal and monitoring of contaminants, such as nucleases and extraneous DNA, and creates new criteria for water purity and water system design. Current water purification technologies are reviewed, and a system designed to provide type I water is discussed.