Body fluid samples are usually delivered to the hematology and cytology laboratories for detection of cellular components. Hematology expertise of medical technologists provides screening results for suspicious malignant cells, whereas the cytology expertise of pathologists provides the presence of cancer cells at a diagnostic level rather than at a screening level. However, these results do not achieve 100% sensitivity or specificity.
A retrospective study was carried out by Shiow-I Lin and colleagues of National Cheng Kung University Hospital, Taiwan to evaluate the clinical practice values and compare the diagnostic ability and performance of hematology and cytology laboratories on the detection of body fluid malignancy. Since the body fluid malignancy is not fully detectable by the cytology department only, an effort to explore the possibility of compensation using hematology laboratory results is commendable.
The case for this study was selected from the body fluid sample duplicates submitted for testing in the hematology and cytology laboratories of National Cheng Kung University Hospital from 2015 to 2016.
Kappa statistics was used to evaluate the agreement of body fluid malignancy between the hematology and cytology laboratories and the differences between the groups were assessed by chi-square test. SPSS software was used to conduct statistical analysis.
Out of 248 body samples, the matched reports of malignancy between the hematology and cytology laboratories were 105 (42.3%) positive and 106 (42.7%) negative. After 6 months follow-up, malignancy was confirmed in 141, and 107 were without malignancy. The hematology reported 15 false negative cases and no false positive, whereas the cytology laboratory reported 20 false negatives and 1 false positive.
This study comprised 19 types of malignancy, and most of the body fluid malignancy came from lung cancer and breast cancer cells, which mainly exfoliated in pleural effusions. No major differences between the cancer types were noticed among the body fluid malignancy reports by the hematology and cytology laboratories. The dominance of malignancy from lung and breast cancers involving the pleural fluid might be due to the high sensitivity and comparable detection in the hematology and cytology laboratories.
In total, the study showed that the hematology laboratory could attain diagnostic competency comparable to the cytology laboratory for diagnosis of body fluid malignancy.
Compared to the previous studies yielding sensitivities ranging from 23% to 64.9%, the present study achieved 89.4% sensitivity. The outcomes of the detection of body fluid malignancy are determined by different factors including the body fluid sample, cancer types, stain of specimen, and personal skills.
The major limitations of this study were that the study was conducted with cases for testing in both the hematology and cytology laboratories, and the numbers of cancer types were small considering the majority of pleural fluid specimens.
Based on the comparison between the hematology and cytology, the authors concluded that by improving the skills of the technologists of the hematology laboratory in identifying cell morphology, the diagnostic values in body fluid malignancy could be improved, and the hematology laboratory would achieve comparable competency similar to the cytology laboratory.
Shiow-I Lin, Jen-Yu Tseng, Kung-Chao Chang, Kung-Chia Young. Detection of Malignancy in Body Fluids: A Comparison of the Hematology and Cytology Laboratories. Journal of Applied Clinical Pathology 2018;1(1):5. [View Article]