Accuracy of the Measured Depth of Histologic Sections Compared to the Gross Specimen Measurement
Gretchen W Frieling, Thomas P Ahern, Steven R Tahan. Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Channing Laboratory, Harvard Medical School, Boston, MA
Background: Tissue processing by histology labs is a complicated process, involving replacement of water with a tissue-solidifying medium to allow thin sections to be cut and mounted onto glass slides. This process has the potential to alter tissues. To our knowledge, no previous study has evaluated factors potentially associated with changes in tissue dimensions during processing.
Design: We prospectively analyzed 120 skin specimens with a minimum excisional depth of 0.5 cm. We measured the depth from superficial epidermis to deepest point of: 1) intact gross specimen (gross-I), 2) deepest gross section after sectioning (gross-S), and 3) histologic section of the corresponding tissue block mounted on a glass slide (hist-D). Change in dimension (CID) was calculated as the difference between hist-D and gross-S. These measurements were compared with patient sex, age, anatomical location [head/neck (H/N), trunk or extremity], and technologist. Comparisons were made with Pearson correlation coefficients, t-tests, Kruskal-Wallis rank tests and ANOVA.
Results: Mean patient age was 56 (±17.8). Trunk was the most common site (43%). There were 15 technologists, and each processed between 1 and 17 specimens. Mean gross-I and gross-S were not significantly different from mean hist-D (mean gross-I=8.4mm, mean gross-S=8.7mm, mean hist-D=8.6mm). The correlation coefficients between gross-I and gross-S with hist-D were 0.80 (95% CI: 0.72-0.86) and 0.85 (95% CI: 0.79-0.89), respectively (P<0.0001 for both). No difference in CID was found for sex (P=.21), age (P=0.79), or anatomic site (P=0.32). Specimens from the H/N category yielded smaller CID values (mean ranks: H/N 50.19, Upper Extremity 52.06. Lower Extremity 56.25, Trunk 60.89, Genital 93.50; global P=0.32). Gross-I and gross-S were both negatively correlated with CID, (rho=-0.27 (95% CI: -0.44, -0.91) and -0.29 (95% CI: -0.46, -0.12), respectively). The difference in mean CID between highest and lowest technologists was 3.55.
Conclusions: Processing of tissues for histological analysis is an intricate process with significant potential to change dimensions, and thus altering diagnoses and patient management. We found a negative correlation of both gross-I and gross-S with CID, implying that specimens with greater excisional depth and greater depth of deepest section undergo the least absolute change in size after processing. Age, sex, and anatomic site did not significantly influence the CID.
Category: Quality Assurance
Monday, March 19, 2012 1:00 PM
Poster Session II # 256, Monday Afternoon