Venipuncture - blood collection, Biology

Assignment Help:

Venipuncture:

patient should be seated or supine for at least 20 minutes before sampling. An arm with an inserted intravenous line should be avoided. The median cubital vein in the anticubital fossa is the preferred site for collection of blood in adults. After selection of the vein, the area should be cleaned with a prepackaged alcohol swab or with a gauze pad saturated with 70% isopropanol. The skin should be allowed to dry in the air. No alcohol should remain on the skin, because traces may cause hemolysis. After cleaning, a tourniquet is applied above the intended site to apply pressure upon the vein.

 Tourniquet should not be left in position for more than one minute (marked changes of hemoconcentration is observed after 3 min.), and the patient should not allowed to pump his or her fist while the tourniquet is in place (it cause an increase in plasma potassium, phosphate, and lactate concentration).

Stress associated with blood collection can have effects in patients at any age. Plasma concentration of cortisol and growth hormone may increase.

Blood is then could be collected using either an evacuated collection tube or by syringe. During collection of blood you should avoid vigorous suction in the syringe and avoid forceful transfer to the receiving vessel as this may cause hemolysis of blood. Hemolysis will interfere with chemical procedures which are based on colorimetry. Erythrocytes have higher concentration of potassium, thus any hemolysis will lead to erroneous higher potassium in plasma or serum.

Hemolysis may be avoided by making sure that the container of blood (blank tube) is not wet because presence of water (which is hypotonic solution) will cause hemolysis. If we want to collect SERUM, then blood should be transferred to a clean, dray tube slowly and allowed to clot for 15-30 minutes at room temperature for completion of coagulation, the clot is dislodged from the wall by mean of a glass rod then the tube is centrifuged for 5 minutes to provide a clear supernatant serum for further use in analysis.

Serum is usually the standard sample for performing most of the biochemical blood tests like sugar, urea, creatinine, uric acid, protein, albumin, electrolytes, cholesterol, most enzymes, calcium, phosphate, etc. Serum is kept in the dark if the sample will be used for bilirubin estimation If we want to collect PLASMA or whole blood, then blood should be transported from the syringe to a tube with an anticoagulant and make sure to mix the blood with the anticoagulant by rotating the container between hands and to avoid shaking and forth production. Whole blood is rarely required for clinical tests; indeed only for blood gas, ammonia, and some trace elements.


Related Discussions:- Venipuncture - blood collection

Pattern of limb development, Pattern of Limb Development The first vi...

Pattern of Limb Development The first visible sign of limb development is the appearance of ridge or thickening on each lateral side of the embryo of amniotes. The ridge call

How sex occurs in bacteria, Q. How sex occurs in bacteria? Occurrence o...

Q. How sex occurs in bacteria? Occurrence of sex in bacteria was first described by Edward Tatum and Joshua Lederberg in 1946 (Nature, volume 158, page 558) who were studying m

Mitral valve, This valve has the same basic features as  of the Tricuspid V...

This valve has the same basic features as  of the Tricuspid Valve. It has an anterior and a posterior cusp. The anterior cusp is larger and is attached on the upper right part of t

Principal sources of excessive nitrate and phosphate, What are the principa...

What are the principal sources of excessive nitrate and phosphate in rivers and lakes? Excessive nitrates and phosphates come majorly from sewage effluents and intensive agric

What is biological contaminants, Q. What is Biological Contaminants? Yo...

Q. What is Biological Contaminants? You may recall reading about food borne diseases caused by the consumption of contaminated food items in the last unit. In the

What is flap tearing, What is Flap tearing Poor preoperative surgical p...

What is Flap tearing Poor preoperative surgical planning can result in flap of small size with inadequate exposure of the underlying bone. In an effort to increase the visibili

Concept of fitness, While discussing the Darwinian premise of natural selec...

While discussing the Darwinian premise of natural selection we observed that the term selection is synonymous with non-random reproduction, and that the success of the survivors is

Explain the meaning of transfer of culture, Explain the Meaning of Transfer...

Explain the Meaning of Transfer of Culture Transfer of culture can be done from one liquid media to another liquid media or from liquid to solid media or vice versa. The steps

Diseases, what diseases are caused by trypanosoma and entameoba histolytica...

what diseases are caused by trypanosoma and entameoba histolytica

What is the ranges of tolerance and performance optima, What is the ranges ...

What is the ranges of tolerance and performance optima? Ranges of Tolerance and Performance Optima :   When it comes to physical factors or resources, most species are able to

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd