Chromosome Analysis, Lymphoid Tissue
Method Description Describes how the test is performed and provides a method-specific reference
Tissue is dissociated using enzymes and/or mechanical means, and the tissue is transferred to tissue cultures. The cultures are incubated at 37 degrees C with 5% carbon dioxide (CO2), 5% oxygen (O2) and 90% nitrogen (N2). Cultures may be harvested starting at 24 hours after set up and include harvests up to and including 144 hours (5 days) after set up.
The harvest procedure involves treating the cells with colcemid, and hypotonic solution, then fixing the cells with glacial acetic acid and methanol. Metaphase cells are dropped onto microscope slides and are routinely stained by G- or Q-banding. Twenty metaphases are usually examined. If an abnormal clone is not detected in the unstimulated culture, a 72-hour mitogen (CpG) culture may be analyzed if available. Minimal evidence for the presence of an abnormal clone is defined as 2 or more metaphases with the same structural abnormality or chromosome gain (trisomy), or 3 or more metaphases lacking the same chromosome. Five to 10 metaphases are captured using a computerized imaging system and 1 or more representative karyograms from each clone are prepared to document the type of abnormality and permit systematic interpretation of the anomalies. (Witzig TE, Phyliky RL, Li CY, et al: T-cell chronic lymphocytic leukemia with a helper/inducer membrane phenotype: a distinct clinicopathologic subtype with a poor prognosis. Am J Hematol 1986;21:139-155; Dewald GW, Noel P, Dahl RJ, Spurbeck JL: Chromosome abnormalities in malignant hematologic disorders. Mayo Clin Proc 1985;60:675-689; Inwards DJ, Habermann TM, Banks PM, et al: Cytogenetic findings in 21 cases of peripheral T-cell lymphoma. Am J Hematol 1990;35:88-95)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m. CST.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test