The yield of malignancy for early fixation versus routine fixation of Pleural fluid samples

ABSTRACT

Background@#The etiology of pleural effusion remains unclear in nearly 20% of cases. One way to diagnose malignancy is by doing pleural fluid cytology. There are factors that influence the yield of pleural fluid cytology and one of them is appropriate and timely fixation of samples. Currently, there is no local consensus regarding the timing with which the specimen should be fixed.@*Objective@#The study aims to compare the yield of malignancy between early fixation versus usual fixation of pleural fluid samples, meaning there is no set time for fixation to be done.@*Methodology@#The study employed a prospective cross-sectional research design. All patients with pleural effusion who fulfilled the criteria set by the study were included. Two sets of pleural fluid samples were collected amounting to 20cc each. First sample was assigned as Bottle #1 and placed immediately with fixative while the second sample was assigned as Bottle #2. Bottle #2 underwent routine fixation which follows no fixed or standard time of fixation. The time difference between the fixation of two sample groups greatly varied with Bottle #1 fixed immediately right after collection while Bottle#2 depends on the time it will be processed by the laboratory personnel. Both samples were submitted for cell block and cell cytology reading.@*Results@#Characteristics of the 55 patients included in the study showed age group range from 41 to 65 years of age, with 27 male and 28 female patients. Only one third had history of smoking. There were 21.82% who had family history of cancer and with and suspicious mass on chest radiograph. Out of 55 patients, 29 patients had history of previous diagnosis of cancer, 23 had recurrent pleural effusion, and 28 had chest radiograph with suspicious nodules. Based on gross appearance, there were 20 serous and 21 sanguineous pleural fluid noted. Mean cell count was high (1,115.50 ± 741.02) with lymphocytic predominance (82.56 ± 24.46). Elevated protein concentration (5,388.25 ± 8,230.46) and LDH (484.17 ± 248.72) were noted. Glucose (8.78 ± 6.68 mmol/L) was low. There were 21 patients who had high WBC, 24 with high protein and 16 with elevated LDH. There were 3 patients who were positive for AFB and none for KOH. Comparative analysis showed that the pleural fluid samples assigned to the routinely fixed group which were handed to the nurse after thoracentesis, then forwarded to the laboratory through a ward laboratory aide or patient watcherfor fixation with with 95% alcoholby thelaboratory personnel significantly had a longer duration of 406.62 minutes as compared to immediately fixed at 12.27 minutes (P<0.01). For diagnosis of malignancy, significantly more cases were diagnosed in the immediately fixed group with 36.36% cases versus 18.18% (p=0.016).@*Conclusion@#Among patients with suspected malignant pleural effusions, early fixation of pleural fluid samples resulted in higher histopathology yields as compared to those fixed after going through the routine fixation.