FISH: A Little Known Lab Test for an Important Disease

country joeAnd it’s one two three…

…what are we fighting for?

Country Joe McDonald and the Fish-1965

It is early morning, 6:30 a.m. I sit in a dark room, staticky music from WXRT playing on the beat up radio in the corner. The setting is ripe for meditating, but my meditation consists of peering through a large, clunky, microscope. I see glowing blobs of blue, shiny pairs of dots reds and yellows, greens and aquas. I make notes on a score sheet. I am without a rod and reel, there is no lake or river nearby, but I am on my morning FISHing trip.

I’ve talked about prostate cancer and looking at biopsies a few times here, but we actually process more specimens related to bladder cancer. Sometimes we get small biopsy samples, taken by the urologist during a cystoscopy procedure, but more often it’s the Yellow River that provides the material for us to analyze.

Most people don’t realize that urine contains a myriad of cells that drift off the inner lining of the bladder into your pee. Our job in the lab is to look at those cells and determine if any of them are suggestive of cancer in the bladder. How do we do it? We have a couple of different methods.

Our simplest test is called cytology. Our great lab team first centrifuges and then processes the urine specimen until a thin layer of cells covers a glass slide. Those cells are then stained with the Papanicolaou stain, and yes that is the same one used in a traditional Pap smear. Several pairs of eyes look at the stained cells, and any significantly abnormal ones are noted and reported. We do about 50 of those cases a day.

But my early mornings are spent in the dark room FISHing. FISH, which stands for Fluorescent In-Situ Hybridization, is a technique in which a glass slide covered with cells is stained with probes that mark specific chromosomes in each cell. Each probe is formulated to light up a different color when examined in the dark under ultraviolet light. Our special microscope is equipped with a UV light and four different wavelength filters. lab fishWe examine each cell, and by switching filters are able to count four different chromosomes. Two of a kind is normal, when a cell has an increased number of chromosomes, we start to worry.

Our system is automated. It is linked to a computer that can do the initial screening of the cells and then take digital photographs for the pathologists to examine. But I like to get into the FISH room in the morning, turn off the lights, and look at those cells myself.  Peacefully floating down the FISH river is a great way to start the day!

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