Analysis serum

These analyses play a critical role in diagnosing and monitoring a wide variety of disorders (see Table 3), and a typical central hospital laboratory typically carries out many thousands of such tests every month. In order for a new testing procedure to be accepted clinically it must meet well-defined accuracy and precision standards. Although practical considerations such as the degree of automation also play a role in the acceptability of novel methods, these issues lie outside the scope of this article. In this section we present the current state of the art in the IR-based analysis of serum. 

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The column used for blood serum analysis was 100 cm long, 1 mm in diameter and packed with RP 18 reversed phase having a particle size of 10 pm. A concave gradient program was used to develop the separation over a period of 45 min. at a flow rate of 50 pl/min. The initial solvent was 75% methanol 25% water and the final solvent was pure methanol. 

It is, however, important to mention here that certain other routine procedures also carried out in a clinical laboratory fall beyond the scope of biomedical analytical chemistry, namely microbiological assays, heamatological assays, serum analysis, urine analysis and assays of other body fluids. 

OHF is almost exclusively excreted without undergoing -ring reduction and conjugation and can be measured in urine by HPLC-MS. A useful diagnostic ratio is that of 18-OHF UFF, which is normally about 5 1 and rises to 50 1 in GRA. Serum analysis is used to measure aldosterone (elevated in the disorder) and cortisol, but not typically for 18-OHF. 

The DHPT PT ratio is proportional to the DHCicholesterol ratio and profile analysis can therefore be used diagnostically as an alternate to serum analysis (Fig. 5.3.6). The enzyme deficiency is never complete and the severity of the condition can be ascertained by determining the DHPTiPT ratio. 

GC-MS SIM analysis for prenatal diagnosis requires a different calibration standard from that used for urine from children and adults. Table 5.3.12 shows the steroids present in our external standard and the monitored ions. For serum analysis we employ the highly sensitive ion-trap MS/MS technique described at the beginning of this chapter. Many steroid ratios have been calculated that can be used to distinguish causes of low-estriol, a few that we consider useful are given below, values considered positive for particular disorders are in parenthesis. 

Sjodin A, Thuresson K, Hagmar L, et al. 1999b. Occupational exposure to polybrominated diphenyl ethers at dismantling of electrons. Ambient air and human serum analysis. Organohalogen Compounds 43 447-451. 

In the case of most chemicals, urine analysis provides less precise information than blood serum analysis about the donor s instantaneous state of health. This is because the chemicals build up over time as filtered by the kidney and are diluted by variable amounts of water in the bladder depending upon the donor s hydration state. However, the easy availability of urine, compared with blood, means that repeated urinalysis can monitor a person s state of health with little pain or disruption. As noted above, another major use of urine analysis is the detection of breakdown products from medications or illegal drugs. 

Clinical Serum Analysis of Rats Fed Browned or Control Proteins... 

Using SELDI technology, a-defensin isoforms were found to be elevated in serum from colon cancer patients and in protein extracts from CRC [59]. This result was confirmed by expression analysis of microarray data obtained from 283 tumors and normal tissues followed by serum analysis of colon cancer patients and controls by ELISA. This study yielded a diagnostic sensitivity of 70%i and specificity of 83% for a-defensin in colon cancer [60]. Although these figures appear too low for developing a screening test, this... 

The antibodies are usually found in the CSF as well as in the serum, and there is often evidence of intrathecal antibody production, that is a CSF serum antibody ratio exceeding 1 [159, 160], and CSF oligoclonal bands [144]. Serum analysis of onconeural antibodies is regarded as sufficient for practical clinical purposes [157], except for the Tr antibody, which is sometimes detectable in the CSF only [70]. 

Polhuijs, M., Langenberg, J.P., Benschop, H.P. (1997a). A new method to detect organophosphate exposure serum analysis of victims of Japanese terrorists. In m-CB Medical Treatment Symposium, May 26-30, 1997, Hradec Kralove, Abstracts, p. 25. 

Human serum analysis Eluent A (0.05 M perchloric acid ACN = 60 40)/eluent B (0.05 M perchloric acid ... 

The concentration of lithium in serum, plasma, urine, or other body fluids has been determined by flame emission photometry, atomic absorption spectrometry, or electro-chemically using an ion-selective electrode. Serum analysis, the most useful specimen for lithium monitoring, is most commonly quantified by automated spectrophotometric assay. 

Although commercial assays for direct serum analysis of rTj are available, kit procedures are not as convenient as are those for other thyroid hormones and no rTs method has been adapted to an automated platform because this measurement has no recognized diagnostic value. In comparison with the reference method described by Chopra,the typical kit procedure is relatively fast it requires a 3-hour incubation at room temperature, followed by polyethylene glycol precipitation and centrifugation. The entire procedure requires less than 6 hours to perform. 

Incomplete atomization of the analyte causes so-called chemical interferences. They are due to the fact that atomic absorption can only occur with free atoms. Thus reactions in the flame which lead to the formation of thermally stable species decrease the signals. This fact is responsible for the depression of calcium signals in serum analysis by the proteins present, as well as for the low sensitivities of metals that form thermally stable oxides or carbides (Al, B, V, etc.) in flame AAS. A further example of a chemical interference is the suppression of the absorbance of earth alkali metals as a result of the presence of oxyanions (X) such as aluminates or phosphates. This well-known calcium-phosphate interference is caused by the... 

In clinical analysis, flame AAS is very useful for serum analysis. Ca and Mg can be determined directly in serum samples after a 1 50 dilution, even with microaliquots of 20-50 pL [314]. In the case of Ca, La3+ or Sr2+ are added so as to avoid phosphate interferences. Na and K are usually determined in the flame emission mode, which can be realized with almost any flame AAS instrument. The burner head is often turned to shorten the optical path so as to avoid self-reversal. For the direct determination of Fe, Zn and Cu, flame AAS can also be used but with a lower sample dilution. Determination of trace elements such as Al, Cr, Co, Mo and V with flame AAS often requires a pre-concentration stage, but in serum and other body fluids as well as in various other biological matrices some of these elements can be determined directly with furnace AAS. This also applies to toxic elements such as Ni, Cd and Pb, which often must be determined when screening for work place exposure. When aiming towards the direct determination of the latter elements in blood, urine or serum, matrix modification has found wide acceptance in working practices that are now legally accepted for work place surveillance, etc. This applies e.g. for the determination of Pb in whole blood [315] as well as for the determination of Ni in urine (see e.g. Ref. [316]). 

The oldest of the spectroscopic radiation sources, a flame, has a low temperature (see Section 4.3.1) but therefore good spatial and temporal stability. It easily takes up wet aerosols produced by pneumatic nebulization. Flame atomic emission spectrometry [265] is still a most sensitive technique for the determination of the alkali elements, as eg. is applied for serum analysis. With the aid of hot flames such as the nitrous oxide-acetylene flame, a number of elements can be determined, however, not down to low concentrations [349]. Moreover, interferences arising from the formation of stable compounds are high. Further spectral interferences can also occur. They are due to the emission of intense rotation-vibration band spectra, including the OH (310-330 nm), NH (around 340 nm), N2 bands (around 390 nm), C2 bands (Swan bands around 450 nm, etc.) [20], Also analyte bands may occur. The S2 bands and the CS bands around 390 nm [350] can even be used for the determination of these elements while performing element-specific detection in gas chromatography. However, SiO and other bands may hamper analyses considerably. 

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