Biotech Articles
Publish Your Research Online
Get Recognition - International Audience

Request for an Author Account   |   Login   |   Submit Article
 
 
HOME FAQ TOP AUTHORS FORUMS PUBLISH ARTICLE
 
 

Fine Needle Aspiration Technology

BY: Preethi Venkateswaran | Category: Applications | Submitted: 2011-05-05 18:01:43
       No Photo
Article Summary: "Standard disposable 27-22 guage, 30-50mm long needles are suitable for superficial, palpable lesions. 25- guage needles are mostly used. Yield with such needles is however less, samples are however adequate and smears are of better quality due to lesser admixture with blood. 27 guage needles are used mainly for children and for .."


Share with Facebook Share with Linkedin Share with Twitter Share with Pinterest Email this article
     


Preparation for biopsy:
Needles: Standard disposable 27-22 guage, 30-50mm long needles are suitable for superficial, palpable lesions. 25- guage needles are mostly used. Yield with such needles is however less, samples are however adequate and smears are of better quality due to lesser admixture with blood. 27 gauge needles are used mainly for children and for sensitive areas. Needles of 23-22 guage give best yield but thinner needles are more efficient. Larger needles are used if cell volume is more important than the smear quality for example to provide material for ancillary tests. 22 guage are most suitable for deep biopsies. Core needle biopsy (CNB) can provide tissue from fibrotic hypocellular lesions from which the yield of FNB is often inadequate. CNB has greater risk and trauma. FNA is a fine needle biopsy. Good quality disposable 5-20ml plastic syringes that produce a good negative pressure and fit into a syringe holder.

Sterile Containers: Sterile containers need to be used which have the balanced salt solution. Special cell cultures are required at times.

Slides: Glass slides thoroughly cleaned and free from grease. The aspirate can be smeared between 2 standard microscopic slides. Air dried smears are used.

Fixatives: Routine wet fixative of smears; either 70-90% ethanol in coplin jars is used. Carnoy's fixative has advantage of lysing red blood cells; glutaraldehyde and 10% buffered formalin should be available if tissue fragments for paraffin embedding are obtained.

Stains and Microscope: Differential quick stain or haematoxylin-eosin stain is used for proper viewing through the lightweight portable microscope.

Patient Preparation: A formal written consent is taken from the patient before any biopsy test. Pre biopsy sedation is rarely required. Atropine is recommended in preparation for transpleural biopsy to prevent unlikely risk of vasovagal reflex. Spray anaesthesia of a local anaesthetic is useful.

Biopsy Procedures: Insertion of needle in vertical position, this is needed for the better control and positioning of the needle.

Aspiration:The negative pressure created does not tear cells but merely holds the tissue against the sharp cutting edge of the needle, which cuts softer tissues.

Fibrous stromal cells are poorly represented in the aspirate, whereas cellular or myxoid stromal material is easily sampled. A maintained negative pressure must be released before the needle is withdrawn. Even so, a good part of aspirate is drawn up into the hub of needle and the aspirate must be rinsed with fluid to recover specimen.

Fine needle without aspiration: This technique is based on observation that the capillary pressure in a fine needle is sufficient to keep the detached cells inside lumen of the needle. This gives an excellent feel of consistency of tissues. This method suited well for biopsy of thyroid and other vascular tissues.

Failure to obtain sample: If the needle misses the target tangentially thus aspirating cells from the benign region but not from malignant region then it gives a scant yield.
Processing the sample is the next essential step.

Direct smearing: An aspirate is dry if it has creamy consistency and has numerous cells in a small amount of tissue fluid. A wet aspirate consists of smaller number of cells suspended in fluid or blood.

Macroscopial appearances of smears
(a) Optimal smear of dry sample carcinoma of prostate. Cell clusters seen as blue dots.
(b) Smear of wet sample where blood is at top end and cell clusters concentrated and evenly spread in thin mid portion.
(c) Poorly presented smears.

If smears are large they should be transferred to many slides and haematoxylin-eosin is used for immunostaining. Good cell fixation depends on rapid drying this is enhanced by moderate heat.

Indirect smearing: Thin fluid samples are the best processed by centrifugation on cytocentrifuge. Millipore or nucleopore film is an alternative but has been less satisfactory. Optimal pressure of cells and nuclear shapes are important in diagnosis of malignant lymphoma. Hank's balanced salt solution with addition of 10-20% ideal.

Tissue fragment and cellblocks: Fragments are the best assemble with a drop of blood adding thrombin to produce a clot. Tissue fixed in 5-10% buffered isotonic formalin and processed.

Fixation and staining: Two different methods for fixation and staining are used in FNAC. Air drying followed by heamatol stain such as MGG, alcohol fixation and staining according to Pap or with H & E. Air drying is a sensitive method to produce a thin and even film of material on side.

About Author / Additional Info:
A budding research writer

Search this site & forums
Share this article with friends:



Share with Facebook Share with Linkedin Share with Twitter Share with Pinterest Email this article

More Social Bookmarks (Digg etc..)


Comments on this article: (0 comments so far)

Comment By Comment

Leave a Comment   |   Article Views: 5307



Additional Articles:

•   Genome-Wide Association Study: SNPs to Disease Associations

•   Post Harvest Management of Onion

•   Metabolomics and Their Applications

•   Environmental Pollution - List of Most Common Pollutants




Latest Articles in "Applications" category:
•   Flavor Biotechnology: Part -1

•   Flavor Biotechnology: Part -2

•   Genetic Engineering Extended the Shelf-life of Fruits

•   Biomedical Informatics - From Cells to Populations in the IT Way

•   The Concept of Biotechnology: Understanding Various Applications/Uses

•   In Vitro Fertilization Procedure - Applications, Advantages and Disadvantages

•   Fluorescence-Activated Cell Sorting

•   Directed Evolution

•   Fermentation, and its Control

•   Advanced Fermentation Control Strategies

•   Methods of Purification of Enzymes

•   Extremophilic Microbes - Organisms Living in Extreme Conditions

•   Colorful Bacteria

•   Importance of Phytoremediation

•   Conservation of Microbes

•   Sewage Bacteria - Strictly Anaerobic, Aerobic and Facultative bacteria

•   Microbial Growth Substrates

•   Injuries to Microbes

•   Asepsis and its Importance



Important Disclaimer: All articles on this website are for general information only and is not a professional or experts advice. We do not own any responsibility for correctness or authenticity of the information presented in this article, or any loss or injury resulting from it. We do not endorse these articles, we are neither affiliated with the authors of these articles nor responsible for their content. Please see our disclaimer section for complete terms.
Page copy protected against web site content infringement by Copyscape
Copyright © 2010 biotecharticles.com - Do not copy articles from this website.

ARTICLE CATEGORIES :
Agriculture Bioinformatics Applications Biotech Products Biotech Research
Biology Careers College/Edu DNA Environmental Biotech
Genetics Healthcare Industry News Issues Nanotechnology
Others Stem Cells Press Release Toxicology  


  |   Disclaimer/Privacy/TOS   |   Submission Guidelines   |   Contact Us