Test strip screening

A test strip enzyme immunoassay that could not discriminate between the 17 - and 17 -stereoisomers but allowed on-site screening of urine samples within 45-60 min was also reported (118). In this assay, 17, 19-nortestosterone was coupled to bovine serum albumin through a hemisuccinate bridge at the 17-position (119). This conjugate was used to raise polyclonal antibodies that would... 

A useful qualitative screening test for salicylic acid is performed by adding a few drops of glacial acetic acid or 0.1N hydrochloric acid to 1 ml of urine, followed by 3 drops of 10% ferric chloride solution. A burgundy red color appears and persists if salicylic acid is present (color may turn reddish brown in the presence of phenothiazines). A serum salicylate level can be obtained in most laboratories. Commerically available test strips may be used with urine as well as serum or plasma to determine the presence of salicylic acid. These tests react only with salicylic acid and therefore do not work on stomach contents or pills, but any salicylate is hydrolyzed in the body to salicylic acid and would be present as such in blood or urine (15). 

Jung K, Pergande M, Priem F, Becker S, IClotzek S. Rapid screening of low molecular mass proteinuria Evaluation of the first immunochemical test strip for the detection of tti-microglobulin in urine. Eur J Clin Chem Clin Biochem 1993 31 683-7. 

Kutter D, Thoma J, Kremer A, Hansen S, Carol R. Screening for oligoalbuminuria by means of Micral-TestTM II. A new immunological test strip. Eur J Clin Chem Clin Biochem 1995 33 243-5. 

A number of semiquantitative assays for screening for increased UAE are available. These test strips, most of which are optimized to read positive at a predetermined albumin concentration, have been recommended for screening programs. In view of the wide variability in UAE, it must be borne in mind that a "normal value does not rule out renal disease. Because these assays measure albumin concentration, dilute urine may yield a false-negative test result. Refrigerated urine samples should be allowed to reach at least 10 °C before analysis. Albu Screen and Albu Sure (Cambridge Life Sci-... 

Marshall SM, Shearing PA, Alberti KG. Micral-test strips evaluated for screening for albuminuria. Clin Chem 1992 38 588-91. 

A third DOT-approved device (Alco-Screen 02, Chemat-ics, Inc., North Webster, Ind.) consists of a plastic test strip suitable for insertion under the subject s tongue or into collected sahva. After saturation of the reaction pad with saliva and a 2-minute incubation period, an ADH-diaphorase coupled indicator color bar becomes visible if the ethanol concentration is 0.02 g/dL or greater. 

As noted above, there is a need for a portable rapid blood test to screen for the presence of toxicologically significant concentrations of CN in blood, in order to aid in the immediate definitive diagnosis of CN intoxication on-site. Preliminary studies using Cyantesmo strips, used by water treatment facilities, showed that the strips accurately and semi-quantitatively detected CN in solutions at concentrations > 1 qg ml 1 in 5 min (Rella et al, 2003,2004). 

Our laboratory has been using an Avagotech reader for evaluation of reagents for HIV and cotinine lateral flow assays. Figure 2. shows an example of results for a sample diluted in our prototype HIV antibody detection lateral flow test strips. The Avagotech reader allows the data to be plotted and coefficients of variation to be determined, making the screening more quantitative and less subjective. 

L. Wilhelm, S. Jenckel, and R. Junker, Test strip handling in screening for dmgs of abnse in the clinical toxicological setting, Laboratoriiunsmedizin-Joumal of Laboratory Medicine, vol. 32, no. 3, pp. 168-174, May 2008. 

There are many examples of the use of very small colorimetric devices for POC applications, such as urine dipsticks and test strips for blood sample screening. While not instruments as such, they are based on clever chemistries and reactions and are often single use, throwaway devices. The reagents required for the test are embedded and dried into a strip which is then dipped into the sample, e.g. urine or blood. The colour changes that result are compared to a colour chart, which is usually provided on the side of the container for the test strips. 

M.E. Ploum, W. Haasnoot, R.J.A. Paulussen, G.D. Van Bruchem, A. Hames, R. Schilt, F.A. Hug, Test Strip Enzyme Immunoassays and the Fast Screening of Nortesterone and Clenbuterol Residues in Urine Samples at the Parts per Billion Level , I. Chromatogr., 546, 413-427 (1991). 

You may be called upon to identily whether a powder is anthrax or just a hoax. There are several commercial kits (Figures S4.1 and S4.2) with which to do this, and some manulacturers offer training kits for their tests. The individual tests are relatively inexpensive, hut you can also obtain the components of a useful anthrax screening test at your local pharmacy. The active components of the test are simply urine pH and protein test strips (Figure S4.3). 

Challenges facing the development of in vitro amperometric biosensors (interference rejection, rapid response, reproducibility, response range) have been met in many cases, and commercially available devices based on disposable test strips that incorporate miniature two-or three-electrode electrochemical cells are available for a variety of analytes (see Sect. 10.3.7). Thin-fihn and thick-film technology [80] have been used to mass-produce reproducible sensing elements, and amperometric detection in oxidase-based devices occurs by peroxide oxidation or the oxidation of freely diffusing mediators such as ferricyanide and ferrocene derivatives. The screen-printing process for disposable sensor preparation has also been reviewed [144]. 

Screen printing is a very versatile technique which is employed for the production of all forms of commercially available strip-type chemical sensors (e.g., glucose test strips). 

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