The Principles of Clinical Cytogenetics - Extra Materials - Springer

102 Michael Watson and Steven Gersen
Neoplastic studies Thorough examination of 20 cells when possible. All metaphases
(bone marrow, tumor should be analyzed, and at least two karyotypes should be prepared. If
biopsy or aspirate, more than one cell line is present, at least one karyotype must be preunstimulated
peripheral pared from each. The resolution should be at least 400 bands. When
blood) fewer than 20 cells can be analyzed and an abnormality has been detected,
the number of abnormal and normal (if any) cells is reported. When
fewer than 20 cells can be examined and an abnormality is not detected,
the number of cells studied is reported and additional procedures
(FISH, molecular analysis) or a repeat study, when clinically appropriate,
might be recommended. For studies of minimal residual disease
or engraftment studies, additional metaphases can be examined.
Fragile X syndrome Although guidelines were created for the diagnosis of this disorder
via cytogenetic analysis, current standard of care now involves analysis
via molecular methods. See Chapter 18.
Analysis Worksheets
Laboratories routinely use some form of worksheet to document microscopic analysis data. This is
the technologist’s working document, but becomes part of the patient’s permanent laboratory chart
and, as such, serves as an additional clinical and clerical cross-check.
The analysis worksheet typically includes patient data (patient name, laboratory accession and case
numbers), indication for study, and specimen type. The identification of each slide examined should be
verified, and previous studies might be noted. The technologist performing the analysis and the date should
both be recorded. The microscope being used is often indicated, and microscopic coordinates are recorded
for each metaphase examined, along with other data (slide number, culture of origin, banding method, and
identifiers for relocating the cell). The number of chromosomes and sex chromosome complement are
typically noted, along with other relevant data such as quality of banding, abnormalities, polymorphisms,
or chromosome breakage observed, whether the cell was analyzed and/or imaged, which cells should be
considered for karyotype, and so forth. Finally, a summary of the results, including the patient’s karyotype,
can be included, along with indications of clerical review.
Photography, Imaging Systems, and Karyotype Production
During or upon completion of the microscopic analysis, a specimen is ready to be photographed or
imaged electronically, printed, and karyotyped. Photography or electronic capture are the tools used
to record the microscope image, allowing the chromosomes to be documented and reanalyzed as
necessary. Understanding how to operate, optimize, and maintain the materials and equipment used
in these processes is necessary in order to achieve optimum results from any sample.
Photography
Like microscopy, good photography is not a difficult technique, but is one that relies heavily upon
proper training. Technologists must understand the factors that go into successful transfer of a microscopic
image to film and must be thoroughly familiar with their photomicrographic equipment, as
well as with the chemicals, print papers, equipment, and procedures for developing film and preparing
photographic prints. Knowledge of the resolution and contrast characteristics of print papers and
related developer characteristics are important to those considering individualizing their darkroom
capabilities. Photography could soon become a “lost art,” as more and more cytogenetics laboratories
implement computerized imaging and karyotyping systems (see below).
One of the most important quality controls in photographic processes is accurate labeling of film
and developed prints. A protocol for the laboratory and its darkroom should include a system for
labeling these items, as well as information that will allow a label to be cross-checked against the
microscope analysis worksheet.