Evaluation of four commercially available ELISA assays for the serologic diagnosis of Lyme disease

We evaluated four commercially available ELISAs for detection of antibody to Borrelia burgdorferi with 21 sera from patients with clinically diagnosed Lyme disease and 89 patient control sera. Patient control sera included 28 sera from patients with rheumatoid arthritis (RA), 17 sera from patients with systemic lupus erythematosus (SLE), and 44 sera containing antibodies reported to cross-react in some Lyme disease tests. The ELISAs tested (Cambridge Bioscience, Diamedix, 3M, and Zeus) detect antibodies (IgM and/or IgG) that bind Borrelia burgdorferi antigen attached to microtiter wells. Antibody reactivity in the sera from patients with clinically diagnosed Lyme disease was characterized by using Zeus immunoglobulin class-specific assays (IgM and IgG). Sensitivities in early and late Lyme disease were as follows: Cambridge and Diamedix, 57% and 100%; 3M, 57% and 93%; and Zeus, 71% and 86%. Reactivities within a patient control population were: Cambridge and Diamedix, 3%; 3M, 7%; and Zeus, 10%.     

4种商品化支原体液体培养试剂盒的质量评价

目的比较4种商品化支原体液体培养鉴定检测试剂盒,评价不同厂家支原体试剂的应用效果。方法在相同条件下,选择4种支原体液体培养鉴定试剂和固体培养法对90例保存的临床标本分别进行检测。结果以固体培养法结果为“金标准”,按试剂说明要求,4种支原体液体培养试剂24小时对解脲支原体(Uu)的敏感性和特异性分别为:进口试剂IST为96%和100%、国产试剂1为44%和100%、国产试剂2为68%和100%、国产试剂3为18%和100%;48小时对人型支原体(Mh)的敏感性和特异性分别为:进口试剂IST为95%和100%、国产试剂1为65%和100%、国产试剂2为2.5%和100%和国产试剂3为0%和100%。固体培养结果与进口IST支原体液体培养试剂结果比较差异无统计学意义(P>0.05),但是与国产的3种试剂结果比较差异均有统计学意义(P<0.01)。结论进口IST支原体液体试剂培养鉴定结果与固体培养结果符合率最高,其他3种试剂与固体培养结果符合率较差,结果提示临床检测时,选用支原体液体培养鉴定试剂应慎重。     

Comparison of four methods for free thyroxin

We performed a limited evaluation of four free thyroxin (FT4) reagent kits: the Amerlex-M (AFT4), the Amerlite (LFT4), the MagicLite (MFT4), and the GammaCoat two-step RIA (GFT4). FT4 was measured in specimens from 201 subjects: 19 healthy controls, 14 patients who were thyrotoxic, 13 who were hypothyroid, 59 who had a past history of thyroid disease, seven with thyroxin autoantibodies, seven who were taking amiodarone, and 82 who had no clinical indication of thyroid hormone abnormality. Of these 201 subjects, 78 had a low serum albumin (less than 35 g/L) and 27 had severe nonthyroidal illness. We also investigated 60 pregnant subjects. We found no correlation between thyroxin-binding globulin (TBG) and FT4 in any of the assays, and only the AFT4 method showed a significant correlation with albumin concentrations. The presence of autoantibodies to thyroxin affected the results of all methods except the GFT4 method. All methods showed a decrease in mean FT4 values in late pregnancy. Correlation of patients' clinical state and FT4 results suggested that the reference ranges published by the manufacturers need to be modified for our laboratory.     

Description of two commercially available assays for genotyping of HIV-1

HIV-1 resistance testing is one important part in the diagnostics of antiretroviral treatment and is commonly done by genotyping. Currently, two systems are commercially available and, despite being far from easy to use, these have achieved a high degree of sophistication. Modifications of standard kit protocols might be necessary based on the clinical situation. Although resistance reports based on decision rules are a part of both systems, considerable knowledge and skills are nevertheless required by the user to establish useful clinical data out of detected resistance patterns. Both systems described here have their advantages and disadvantages; a decision for one or the other system needs to be based on individual requirements. The future might lie in so-called 'next-generation sequencing' systems based on pyrosequencing, which enable a high throughput and the detection of minor variants of less than 1%.     

HIV-1 genotyping: comparison of two commercially available assays

HIV-1 resistance testing has become an increasingly important feature in antiretroviral treatment and is commonly accomplished by genotyping. Currently, two different systems are being marketed and, despite being far from easy to use, have achieved a high degree of sophistication. Modifications of the standard-kit protocols may be advantageous in certain situations. Although resistance reports are issued by these systems through interpretation software based on decision rules, it nevertheless requires considerable knowledge and skills by the user to make useful clinical data out of detected resistance patterns. This review describes both systems in detail and discusses their advantages and disadvantages. A final decision on which system to use must be based on an individual's requirements. The future of this field may lie with the use of microarray systems.     

Cytomegalovirus antibody detection by three commercially available assays and complement fixation

Four methods (complement fixation, latex agglutination, qualitative EIA, and quantitative EIA) for detecting antibody to cytomegalovirus (CMV) were compared by testing 103 sera. When ranked according to accuracy, sensitivity, and specificity, the complement fixation test was third, fourth, and first; the latex agglutination test was first, second, and third; the qualitative EIA was fourth, first, and fourth, whereas the quantitative EIA was second, third, and first, respectively. In addition, the complement fixation, latex agglutination, and quantitative EIA systems each satisfactorily detected significant antibody rises in paired sera.     

Evaluation of two commercially available photometers for blood donor haemoglobin measurement

Two commercially available portable haemoglobin measuring devices (Delphi Haemoglobin Meter and HemoCue) were evaluated both within the laboratory and under routine operating conditions in blood donation collection centres. Both meters demonstrated satisfactory accuracy when compared to the reference cyanmethaemoglobin (HiCN) method. Within-run and between-run precision of both meters was satisfactory. There was no significant difference evident between capillary and venous haemoglobin results using either meter. In the main blood collection centre, using Delphi meters, 63.1% of results returned from an external proficiency testing program were acceptable (± 2SD of Quality Control Laboratory result). In satellite centres using Delphi meters 36.5% were acceptable while 60.0% of HemoCue results from satellite centres were acceptable. Assay time was almost twice as long using the HemoCue. The study confirmed the necessity to evaluate equipment and operators under both controlled and routine operating conditions. External proficiency testing programs are recommended to monitor operator performance on a regular basis.     

Evaluation of two commercially available carbon dioxide sampling nasal cannulae

Our study compared two commercially available carbon dioxide sampling nasal cannulae for efficacy of oxygenation and relationship of end-tidal carbon dioxide (Petco ₂) to arterial carbon dioxide (Paco₂). The two-prong nasal cannula (2PNC) has one prong dedicated to delivering O₂ via one naris and the second prong dedicated to sampling exhaled gases via the other naris. The four-prong nasal cannula (4PNC) delivers O₂ via a prong in each naris, and samples exhaled gases via another set of prongs in each naris. Forty six patients were divided into three groups, which received either 2 (n = 15), 3 (n = 16), or 4(n = 15) L/min O₂, respectively, and were studied sequentially with standard nasal cannula (SNC), the 2PNC, and then the 4PNC. At each O₂ flow rate, Pao₂ was equivalent regardless of whether the SNC, 2PNC, or 4PNC was used. Seventy-four percent (34/46) of the 2PNC and 0% (0/46) of the 4PNCPetco2 values were within ±4 torr of the Paco₂ value. The authors conclude that the 2PNC and 4PNC are equally effective compared with an SNC in oxygenating patients, but thePetco2 measured by the 2PNC provides a superior quantitative estimate of the Paco₂ than that obtained by the 4PNC.     

Evaluation of three commercially available kits for serological diagnosis of dengue haemorrhagic fever

Seventy one acute phase serum samples collected during an epidemic of dengue hemorrhagic fever were tested by immunoblot, a rapid immunochromatographic assay and Dengue Duo ELISA for presence of anti dengue IgM and IgG antibodies. A concordance of 81.7% and 76.1% was seen between the three tests for the detection of anti-dengue IgM antibodies and IgG antibodies respectively. The rapid test takes only five minutes, can be easily carried out in most laboratories and compares well with the ELISA and the immunoblot.     

New one-step enzyme immunoassay for free thyroxin

This enzyme immunoassay for free thyroxin (FT4) involves simultaneous incubation of sample and thyroxin conjugated to horseradish peroxidase (EC 1.11.1.7) in antibody-coated tubes at room temperature. The test can be performed in 90 min. It is not influenced by variations in concentrations of thyroxin-binding globulin (TBG), thyroxin-binding prealbumin, or albumin. With increased concentrations of non-esterified fatty acids, the measured FT4 equivalent concentrations increase immediately, indicating displacement of endogenous thyroxin from its binding sites. FT4 values obtained with this assay for 110 samples, including sera with low albumin and high TBG as well as sera of patients treated with heparin, agreed well with those measured by a two-step radioimmunoassay and with the T4/TBG ratio. The measurable range of FT4 with our assay is 2.5 to 65 ng/L. Intra-assay CVs range from 3.4% to 2.2%, interassay CVs from 6.6% to 2.6% at concentrations of 9 to 45 ng of FT4 equivalent per liter.     

5种商品化解脲脲原体培养基质量评价研究

目的评价商品化解脲脲原体（Uu）培养基的质量。方法应用标准菌株Uu4和Uu14比较5种培养基（M、K、L、H、A）的敏感性;以固体培养基的结果作为金标准,应用Uu临床菌株比较5种培养基的敏感性、特异性、阳性预测值、阴性预测值及和金标准的一致度。结果 M和K培养基敏感性最高;M、K、L和H培养基的敏感性〉90.00%;M、K、A培养基特异性达到100.00%;M、K、A阳性预测值为100.00%,而M、K阴性预测值最高,均为99.24%;M、K、L和H培养基与固体培养基一致度满意,而A培养基一致度仅相对满意。结论 M、K培养基质量最佳。市场上检测Uu的培养基存在质量差异,临床上选用宜慎重。     

Evaluation of a commercially available serologic assay for antibodies against tuberculosis-associated glycolipid antigen.

A commercially available enzyme immunoassay developed to detect antibodies to a tuberculosis-associated glycolipid antigen was evaluated for serologic diagnosis of tuberculosis. This was a multicenter study comparing the assay with other methods in 78 patients with active pulmonary tuberculosis and in 54 controls with non-tuberculous lung diseases. Sensitivities were highest for sputum culture (91.0%), followed by immunoassay (79.5%), nucleic acid amplification (77.3%), and finally acid-fast staining of sputum smear (60.3%). Immunoassay and amplification, both rapid methods, had similarly high sensitivity in smear-positive subjects (89.4 and 88.9%, respectively); in smear-negative subjects these two techniques showed low sensitivity (64.5 and 60.0%, respectively). Concordance between the two methods was relatively low (72.0%). With regard to specificity, seven out of ten patients with old tuberculosis had positive result by immunoassay (30% specificity). In the control group, 10 out of 54 patients had positive immunoassay result (72.2% specificity), with notably limited specificity in the elderly. The tuberculous glycolipid assay is a rapid method sufficiently sensitive for detection of tuberculosis infection, even in smear-negative patients.     

Evaluation of a commercially available ELISA assay for detection of Giardia lamblia in fecal specimens

A total of 417 fecal samples preserved in 10% buffered formalin and PVA were submitted to a commercial microbiology laboratory only for the detection of Giardia lamblia. Results from fecal specimens collected from 411 patients with gastrointestinal symptoms were compared using the following methods: (a) standard Ova & Parasite (O&P) concentration; (b) Alexon's ProspecT/Giardia enzyme-linked immunosorbent assay (ELISA) test, and (c) Meridian's Direct Fluorescent Antibody (DFA) Stain. In the 29 specimens in which G. lamblia was detected, 10 were O&P, DFA and ELISA positive, 17 were only ELISA positive and two were only Ova & Parasite and Direct Fluorescent Antibody positive. Of the 29 positive specimens, 22 were confirmed as true positives. The ELISA sensitivity was 91% and the specificity was 98%. The expense associated with these methods to detect the presence of Giardia is $11.00, $8.95, and $12.80, respectively. In symptomatic patients, the ProspecT/Giardia ELISA is a cost-effective, rapid, and sensitive method for detecting the presence of G. lamblia in fecal specimens.     

Frequency analysis of commercially available vibrators

The tonic vibration reflex -- elicitation of a muscle contraction by mechanical vibration -- is a well documented physiological phenomenon of particular relevance to physiotherapy. Among the critical features pertaining to the effectiveness of its use in clinical practice are the mechanical attributes of the vibrator used to elicit the reflex. Because physiological responses differ with vibrations of varying frequency and amplitude, it is necessary to measure these characteristics before a commercial vibrator is used therapeutically: Facilities and equipment for performing such tests are, however, not readily available to physiotherapists. The purpose of this study, therefore, was to measure and compare frequencies of a variety of commercially available vibrators under varying load conditions and over time. Vibrators from major Canadian retail outlets and manufacturers were obtained and, through the use of both mechanical and optical methods, a total of 19 models were frequency-calibrated. The results of the study permit discussion related to the suitability and reliability of each model and provide specific guidance to physiotherapy departments in the selection of appropriate therapeutic vibrators. The results also indicate that the mode of application, such as strapping the apparatus to the patient rather than having the operator hold it in her hand, affects the frequency in some models. The data related to frequency measurements, gained through this study, should enable therapists to make more effective use of commercially available vibrators in motor reeducation.