College of American Pathologists
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  Q & A





June 2008

Question Q. A few oncologists with whom we work ask that their cases be read by their designated pathologists. We do not know why, but we do know the requests are not related to subspecialty. We try to accommodate their requests, but doing so is sometimes difficult. In our department, we share difficult and interesting cases often and have active QA programs. How can we find out the reason for their requests and convince them they’re unnecessary?

A. The oncologists’ concerns may be related to customer service or perceived quality differences, or both. The oncologists appreciate the service provided by their designated pathologists and have probably developed a professional and personal rapport with them. This rapport may help the oncologist and pathologist communicate, which may contribute to the quality and efficiency of the patient care they provide. However, as you point out, at times it is impractical for your group to provide the pathology services that the oncologists and their patients require using only the oncologists’ designated pathologists.

To address this, your group should prepare to have a collegial discussion with the oncologists. The head of or other leader in your group and the designated pathologists may want to arrange to meet with the oncologists to find out what they like about their designated pathologists and to explain your group’s concerns. Before the meeting, develop a plan for including other pathologists in reading their cases.

To develop the plan, ask the designated pathologists how they deal with the oncologists and train the other pathologists in your group to provide the services in a similar manner. For example, the designated pathologists may know the oncologists like to be paged if the diagnosis is available before 4 PM but prefer to be notified the next morning if the diagnosis is available after that time. The purpose of the plan is to provide a transition period during which the oncologists can comfortably develop a similar rapport with other pathologists in your group.

In meeting with the oncologists, explain (preferably citing examples) why having only a certain pathologist, or certain pathologists, read their cases causes difficulties for their practice (for example, delayed turnaround times) and how your group would like to make changes to better serve their practice. In this conversation, consider asking if the oncologists have specific examples of their professional concerns with other pathologists in your group.

The purpose of the meeting is for both parties to understand how they can better work together to provide quality, efficient patient care. Changing the oncologists’ behavior will take time and effort but provides a great opportunity to better serve them and other oncologists who work with your practice.

Edward W. Catalano, MD
Chief of Staff, Palmetto Health
Richland Memorial Hospital
Columbia, SC
Chair, CAP Practice
Management Committee

Question Q. Dark-field microscopy has been used to diagnose Treponema pallidum in its primary stage (chancre). However, with an oral lesion, can the dark-field microscopy be falsely positive due to commensal spirochetes (Treponema microdentium)?

A. There is the potential for false-positivity (reactivity) with commensal oral spirochetes (T. microdentium, T. macrodentium, T. orale, T. denticola, and T. vincentii). These spirochetes inhabit the oral cavity, particularly the gingival crevice and interproximal areas.1 T. vincentii is associated with acute necrotizing ulcerative gingivitis (ANUG, Vincent’s infection). Larsen SA, et al., provide a good review of the laboratory diagnosis for syphilis and address the caveats of dark-field microscopy and being able to distinguish between T. pallidum and the other morphologically similar saprophytic spirochetes, which are present in the oral and genital areas.2 The morphology can be determined by looking at the number of coils, length, width, wavelength, wave depth, rotation, and flexion.

Given the appropriate clinical history, a positive finding on a dark-field examination is good evidence for the diagnosis of syphilis. An advantage to dark-field microscopy is that the test can be positive days to weeks before the appearance of any reactive serological tests. However, a negative result on microscopy does not exclude the diagnosis of syphilis. This could be related to such factors as too few organisms being present, the spirochete having been altered due to treatment, and the quality of the sample/slide preparation. One must also consider that the lesions that occur can be a result of other diseases, such as herpes or chancroid, and the dark-field examination would be negative in those cases. Another limitation of this method is the subjectivity and experience of the person reading the slide because one must be able to distinguish artifacts from the actual pathogen.

Consideration must be given to the specific stage of syphilis the patient may be in because this can affect which diagnostic tests will be positive. The rapid plasma reagin (nontreponemal) and fluorescent treponemal antibody-absorption, or FTA-ABS, tests still remain as standards with regard to diagnosing syphilis in the laboratory.3 However, there are now automated treponemal tests that can be more objective than FTA-ABS.

  1. Schuster GS. Oral flora and pathogenic organisms. Infect Dis Clin North Am. 1999;13:757–774.
  2. Larsen SA, Steiner BM, Rudolph AH. Laboratory diagnosis and interpretation of tests for syphilis. Clin Microbiol Rev. 1995;8:1–21.
  3. Ballard R. Changing times in syphilis serology. Presented at: CDC/APHL teleconference; Jan. 17, 2008.

Rodney C. Arcenas, PhD
Clinical Scientist – Microbiology/Molecular
Pathology Consultants of South Broward
Memorial Healthcare System
Hollywood, Fla.