Common Test-Ordering Errors
Part 3: Misordered Tests

Chromosome Analysis

June 2010

Another common test-ordering error we encounter involves 2 of our chromosome analysis tests. We have 1 orderable for assessing congenital disorders and another for hematologic disorders. Often we find that the congenital disorder chromosome test is ordered when the hematologic disorder test is indicated and vice verse.

While both of these tests use the same specimen type and both begin with a cell culturing step, both the culturing processes and analyses differ significantly, making selection of the correct test critical. Culturing for congenital abnormalities is optimized for chromosome band resolution. This requires extended culturing with a stimulation step to produce high-resolution metaphases for analysis. Typically, the cells are cultured in the presence of phytohemagglutinin to induce mitosis. At culture harvest, agents are added to reduce chromosome condensation and to prevent spindle fiber formation. In contrast, in the culture process for hematologic abnormalities, cells are allowed to divide naturally, without stimulation, and can be cultured and analyzed in a shorter time period. The hematologic chromosome abnormality test is optimized to provide a rapid turnaround time, minimizing time to diagnosis and selection of appropriate treatment, which is critical for patients with hematologic malignancies.

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Jump to section:

• Introduction
• Testing at Mayo Medical Laboratories
• Common MML Test-Ordering Errors
• Misordered Tests
• Genetic Testing
• Cystic Fibrosis
• Cystic Fibrosis
• Multiple Endocrine Neoplasia Type 2 (MEN2)
• Genetic Testing
• Gene Test or Protein/Plasma Test?
• Gene Test or Protein/Plasma Test?
• Chromosome Analysis
• Chromosome Analysis
• Chromosome Analysis, Mitomycin C Stress for Fanconi Anemia, Blood (#81332)
• Conclusion
• Questions?