Blood samples

A blood sample is taken from the patient by the doctor or by some other authorized person. This is to guard against manipulation of the sample by the patient or contamination from the place where the sample is taken. 

the analysis from blood enables a conclusion to be drawn concerning the concentration of an analyte and the possible effect on the concentration of the time at which the blood sample is taken. The correct labeling of both the sample container and the package that contains it and provision of the necessary documentation for the laboratory ensure that the sample will be processed without delay. 

Sample vials can be made of various materials, depending on the supplier of the system for obtaining the sample. This can lead to problems if, for example, they have to be made of glass or other special materials to prevent loss of a particular analyte and they are not availkable from the manufacturer. Unfortunately, the various blood sampling systems are usually incompatible, so that the special vials are effectively non-interchangeable. 

This and other questions relating to the taking, storage or transport of blood samples should preferably be discussed with the laboratory, which should be able to make available any sampling apparatus and transport containers necessary for special analyses. These are then tested for suitability for the analyses concerned. The conditions for taking the sample, possible methods of intermediate storage until shipment, and transport conditions should thus be mutually compatible. 

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Let s consider the following problem. Two sets of blood samples have been collected from a patient receiving medication to lower her concentration of blood glucose. One set of samples was drawn immediately before the medication was administered the second set was taken several hours later. The samples are analyzed and their respective means and variances reported. ITow do we decide if the medication was successful in lowering the patient s concentration of blood glucose ... 

A fourth spectrophotometric method for the quantitative determination of the concentration of in blood yields an Ssamp of 0.712 for a 5.00-mL sample of blood. After spiking the blood sample with 5.00 pL of a 1560-ppb Pb + standard, an SspiPe of 1.546 is measured. Determine the concentration of Pb + in the original sample of blood. 

A fifth spectrophotometric method for the quantitative determination of the concentration of Pb + in blood uses a multiple-point standard addition based on equation 5.6. The original blood sample has a volume of 1.00 mb, and the standard used for spiking the sample has a concentration of 1560 ppb Pb +. All samples were diluted to 5.00 mb before measuring the signal. A calibration curve of Sjpike versus Vj is described by... 

The concentration of the barbiturate barbital in a blood sample was determined by extracting 3.00 mL of the blood with 15 mL of CHCI3. The chloroform, which now contains the barbital, is then extracted with 10.0 mL of 0.045 M NaOH (pH = 13). A 3.00-mL sample of the aqueous extract is placed in a 1.00-cm cell, and an absorbance of 0.115 is measured. 

Pneumatic Pipelines. Pneumatic pipe systems are used to move blood samples, medicine, and suppHes between buildings in hospital complexes cash and receipts in drive-up banks parts and materials in factories refuse from apartment complexes and grain, cement, and many other materials. Most of these are small diameter and usually short however, a 17-km, 1220-mm dia pneumatic pipeline has been used to transport rock in the former Soviet Union since 1981, and a 3.2-km, 1000-mm dia line has moved limestone from the mine to a cement plant in Japan since 1983 (22). 

The analysis of mefloquine in blood, using packed-column sfc, a mobile phase consisting of / -pentane modified with 1% methanol and 0.15% -butylamine, and electron capture detection has been reported (92). The method compares favorably to a previously pubflshed hplc-based procedure having a detection limit of 7.5 ng/mLin 0.1 mL blood sample. 

Because the cells can intermpt the optical path in random orientations, individual scattering intensities are not proportional to cell volume. However, because thousands of cells of each type pass through the flow cell, the effects of orientation can be averaged To a first approximation HCT and platelet crit (PCT), the percentage of blood sample volume occupied by platelets, is proportional to the sums of the scattering intensities of the ted cells and platelets, respectively. MCV can be computed from HCT and RBC, whereas MPV can be computed from PCT and PLT. The accuracy of MCV deterrnined by this method is tied to the RBC accuracy, as is the case for the manual MCV method. Ortho Instmments Corporation s ELT-8 uses these counting and sizing methods. 

Blood alcohol concentration can be determined directly by gas chromatography (Chapter 1). However, this approach is impractical for testing a driver on the highway. It requires that the suspect be transported to a hospital, where trained medical personnel can take a blood sample, then preserve and analyze it. 

Provided a suitable internal standard is available, this is probably the most reliable method for quantitative GLC. For example, the concentration of ethanol in blood samples has been determined using propan-2-ol as the internal standard. 

Amongst other devices used to produce the required atoms in the vapour state are the Delves cup which enables the determination of lead in blood samples the sample is placed in a small nickel cup which is inserted directly into an acetylene-air flame. The tantalum boat is a similar device to the Delves cup in this case the sample is placed into a small tantalum dish which is then inserted into an acetylene-air flame. The use of these devices, especially for small sample volumes, has now been largely superseded by the graphite furnace. 

The effect of a statin is usually determined by measuring fasting plasma lipids and lipoproteins after 4-6 weeks of treatment. Liver enzymes and eventually creatine kinase (in case of myositis liver enzymes are usually also elevated) are measured simultaneously to exclude side effects related to liver and muscles. After the treatment goal has been reached, blood sampling is usually performed 1-2 times a year. 

LITHIUM The dosage of lithium is individualized according to serum levels and clinical response to the drug. The desirable serum lithium levels are 0.6 to 1.2 mEq/L Blood samples are drawn immediately before die next dose of lithium (8-12 hours after the last dose) when lithium levels are relatively stable During die acute phase die nurse monitors serum lithium levels twice weekly or until die patient s manic phase is under control. During maintenance therapy, the serum lidiium levels are monitored every 2 to 4 months. 

Prevention of clotting in arterial and heart surgery, in blood transfusions and dialysis procedures, and in blood samples for laboratory purposes ... 

The nurse notifies the health care provider of any hypoglycemic reaction, die substance and amount used to terminate the reaction, blood samples drawn (if any), the length of time required for die symptoms of hypoglycemia to disappear, and die current status of the patient. After termination of a hypoglycemic reaction, the nurse closely observes die patient for additional hypoglycemic reactions. The lengtii of time close observation is required depends on die peak and duration of the insulin administered. 

Changes in the reference electrode junction potential result from differences in the composition of die sample and standard solutions (e.g., upon switching from whole blood samples to aqueous calibrants). One approach to alleviate this problem is to use an intermediate salt bridge, with a solution (in the bridge) of ions of nearly equal mobility (e.g., concentrated KC1). Standard solutions with an electrolyte composition similar to that of the sample are also desirable. These precautions, however, will not eliminate the problem completely. Other approaches to address this and other changes in the cell constant have been reviewed (13). 

Ultrasound and X-ray equipment are examples of diagnostic medical devices. In-vitro medical devices are distinguished from other diagnostic medical devices, in that a specimen must first of all be removed from the donor. A device worn by a diabetic that continually monitors their glucose via a non-invasive method (near-infra-red energy emissions) would be just regulated as a medical device, whereas a glucosemonitoring device that used a lancet to obtain a blood sample would be an IVD. 

Chromosome aberrations were detected in lymphocytes of individuals acutely intoxicated by methyl parathion by the inhalation route (Van Bao et al. 1974). Blood samples were taken 3-6 days after exposure and again at 30 and 380 days. A temporary but significant (p<0.05) increase was noted in the frequency of stable chromosomal aberrations in the exposed individuals. The study limitations include small sample size, absence of a control group, lack of quantification of exposure levels, and a possible concomitant exposure to other substances via the dermal route. 

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