{"id":1150,"date":"2017-03-16T09:00:00","date_gmt":"2017-03-16T02:00:00","guid":{"rendered":"https:\/\/www.dnacenter-thailand.com\/service\/%e0%b8%81%e0%b8%b2%e0%b8%a3%e0%b8%95%e0%b8%a3%e0%b8%a7%e0%b8%88%e0%b9%82%e0%b8%84%e0%b8%a3%e0%b9%82%e0%b8%a1%e0%b9%82%e0%b8%8b%e0%b8%a1%e0%b9%82%e0%b8%94%e0%b8%a2%e0%b9%80%e0%b8%97%e0%b8%84%e0%b8%99\/"},"modified":"2017-03-16T09:00:00","modified_gmt":"2017-03-16T02:00:00","slug":"%e0%b8%81%e0%b8%b2%e0%b8%a3%e0%b8%95%e0%b8%a3%e0%b8%a7%e0%b8%88%e0%b9%82%e0%b8%84%e0%b8%a3%e0%b9%82%e0%b8%a1%e0%b9%82%e0%b8%8b%e0%b8%a1%e0%b9%82%e0%b8%94%e0%b8%a2%e0%b9%80%e0%b8%97%e0%b8%84%e0%b8%99","status":"publish","type":"dna_service","link":"https:\/\/www.dnacenter-thailand.com\/en\/service\/%e0%b8%81%e0%b8%b2%e0%b8%a3%e0%b8%95%e0%b8%a3%e0%b8%a7%e0%b8%88%e0%b9%82%e0%b8%84%e0%b8%a3%e0%b9%82%e0%b8%a1%e0%b9%82%e0%b8%8b%e0%b8%a1%e0%b9%82%e0%b8%94%e0%b8%a2%e0%b9%80%e0%b8%97%e0%b8%84%e0%b8%99\/","title":{"rendered":"Chromosome Testing by the FISH Technique"},"content":{"rendered":"

The term FISH<\/strong> It stands for Fluorescence in situ Hybridization, a special technique used for chromosome testing beyond the standard techniques. It is used to detect very small chromosomal abnormalities that standard techniques cannot find, or abnormalities not detected by standard techniques, and it allows large numbers of cells to be examined, which suits monitoring treatment in cancer patients. FISH uses the DNA of a gene of interest labeled with a fluorescent dye to bind to the DNA in the patient's cells, letting us see the fluorescence under a microscope. There are many examples of FISH testing, as shown in the images. Our laboratory currently performs FISH testing on samples from various hospitals, for both newborns and blood-cancer patients, at about 250 cases per year. <\/p>\n

Technique <\/strong>FISH<\/strong> This is a method of studying chromosomes or genes at the molecular cytogenetic level, using probes labeled with fluorescent substances that bind to chromosomes at specific positions. It can be studied in cells dividing in metaphase and in interphase, gives a diagnosis in a short time, and can report the percentage of normal and abnormal cells. FISH diagnosis can be performed on samples from blood, amniotic fluid, and bone marrow, with the same preparation steps, but using a probe to stain the slide instead of ordinary staining.<\/p>\n

     – Sex-chromosome testing by FISH is useful for monitoring bone marrow transplant outcomes when the donor and recipient are of different sexes.<\/p>\n

     – Testing for the fusion genes BCR\/ABL and PML\/RARA by FISH can report the percentage of normal cells and of cancer cells carrying the gene rearrangement. This helps in cases where karyotype analysis fails because there are too few metaphase chromosomes for diagnosis, or the chromosome quality is not good enough to karyotype or analyze.<\/p>\n

     – Detecting deleted regions on chromosomes that cause DiGeorge syndrome (22q11.2), Prader-Willi syndrome (15q13.3), Williams syndrome (7q11.23), Alagille (JAG1) syndrome, and Rubinstein-Taybi syndrome<\/p>\n

     – Testing for Down\u2019s syndrome, caused by an increased number of chromosomes 13, 18, 21 (trisomy 13, 18, 21), in interphase by the FISH technique, which helps physicians who must make urgent treatment decisions.<\/p>\n

\nIndications for Molecular Cytogenetics diagnosis <\/strong><\/h4>\n

     – Patients suspected of having a microdeletion syndrome 
\n     – Patients whose chromosome analysis cannot be read clearly, or to find\/confirm an unknown segment of chromosome or a marker chromosome
\n     – Patients for whom metaphase chromosomes cannot be prepared 
\n     – Patients who need urgent results within 3-5 days 
\n     – Patients who have undergone a bone marrow transplant and whose physician needs to know the donor\/recipient cell ratio <\/p>\n

Test limitations <\/strong>
\n     – Cannot detect several types of abnormality from a single test 
\n     – For Prader-Willi syndrome testing, the FISH technique cannot detect abnormalities caused by uniparental disomy; other techniques such as methylation or CA repeat should be used instead. <\/p>\n

Sample collection method<\/strong>
\n     Use the same collection method as for collecting chromosome test samples for each specimen.<\/p>\n

 <\/p>\n

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 <\/p>","protected":false},"excerpt":{"rendered":"

The term FISH stands for Fluorescence in situ Hybridization, a special technique used for chromosome testing beyond the standard techniques. <\/p>","protected":false},"featured_media":1203,"menu_order":0,"template":"","meta":[],"dna_topic":[],"class_list":["post-1150","dna_service","type-dna_service","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/www.dnacenter-thailand.com\/en\/wp-json\/wp\/v2\/dna_service\/1150","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dnacenter-thailand.com\/en\/wp-json\/wp\/v2\/dna_service"}],"about":[{"href":"https:\/\/www.dnacenter-thailand.com\/en\/wp-json\/wp\/v2\/types\/dna_service"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.dnacenter-thailand.com\/en\/wp-json\/wp\/v2\/media\/1203"}],"wp:attachment":[{"href":"https:\/\/www.dnacenter-thailand.com\/en\/wp-json\/wp\/v2\/media?parent=1150"}],"wp:term":[{"taxonomy":"dna_topic","embeddable":true,"href":"https:\/\/www.dnacenter-thailand.com\/en\/wp-json\/wp\/v2\/dna_topic?post=1150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}