Serous effusion indicates accumulation of excess fluid in the body cavities, namely, pleural, and peritoneal the latter also referred to as ascites. Effusion invariably indicates an underlying pathology and constitutes an important diagnostic sample in clinical practice, including oncology.[1] Body fluids from various anatomic sites can be evaluated by cytology. The techniques for collection, transportation, and preparation of Body fluids are of prime importance, as an adequate, well prepared, well stained smear helps in the ultimate goal of an accurate cytopathological diagnosis.[2] The methods of collection and processing of body fluids for cytological diagnosis vary from laboratory to laboratory. To achieve uniformity in this process across our country, the Indian Academy of Cytologists (IAC) has developed these guidelines in consultation with experts across the country for implementation as a standard format in our country for all laboratories providing cytopathology services.

Aims:  The present study was carried out to assess the feasibility of applying the IAC reporting categories to effusions, determine the frequency, and provide an estimate of the risk of malignancy (ROM) for individual diagnostic categories.

The present study was carried out in the Cytopathology Laboratory, Department of Pathology, P.D.U Medical College and Hospital, Rajkot, Gujarat   carried out over a period of 1 year between August 2023 to July 2024. All the cases referred to the department of Pathology from the Department of Surgery, Respiratory medicine, medicine, orthopedics for evaluation of fluid were included in the study. Clinical data and radiological assessment were done in all these cases. Direct smears and cytospin smears were prepared. Cerebrospinal fluid and urine samples were processed by cytospin method (at 2500 rpm for 5 minutes) and all other body fluids were centrifuged (2000 rpm for 10 minutes). The sediment separated from the above procedure was used in preparation of smears on 2 glass slides with frosted ends. One was air dried and stained with Papanicolaou’s stain, Giemsa stain. The other slide was immediately fixed in 95% alcohol and stained with Haematoxylin & Eosin Stain.

A total of 814 effusion samples were received from 785 patients. There were 414 (50.8%) males and 400 (49.2%) female.

TABEL 1. A total of 814 effusion samples were received from 785 patients. There were 414 (50.8%) males and 400 (49.2%) female.

TABEL 2. Majority were pleural (612, 75.1%), followed by peritoneal (123, 15.1%) and other fluid like (CSF, Urine) (79, 9.8 %). The age ranged from 7 months to 92 years.

TABEL 3. There were 22 (2.7%) samples in category 1 (non‑diagnostic), 696 (85.50 %) in category 2 (benign), 11 (1.3%) in category 3 (atypical), 36 (4.4%) in category 4 (suspicious for malignancy) and 49 (6.01 %) in category 5 (malignant).

TABEL 4. Comparison of prevalence rate of serous fluid in different studies.

In Gulia Met al ^[3], out of 161 cases, benign category comprised majority of cases 148 (91.92%), followed by category 3 with 5 cases (03.10%), category 5 having 3 64%. The estimated risk of malignancy calculated for each category from 1-5 was 33.3%, 7.14%, 50%, 100% and 100% respectively. Category 2, which consisted of the majority of cases in our study is consistent with findings from other studies.7-9

The study conducted by Jha et^[4]  al  showed  that  4.26%  of cases  fell  under  category  1, 83.77%  were  in  category  2, 5.2%  in  category  3,  3.25%  in  category  4, and  8.22%  in category 5.7 ROM for categories I-V was 21.42%, 14.9%, 33.3, 90% and 96.4% respectively .

Based on the study conducted by Deep et al^[6], the findings show  that  84.2%  of  cases  were  classified  as  category  2 (benign),  followed  by  category  5  (5.84%),  category  4 (5.84%), category 3 (2.63%), and category 1 (1.46%). The ROM calculated for category 1 in the study was 0%, with all follow-up happened to be benign lesions.  ROM   was   4.4%, 50%, 50%   and   100% respectively for categories 2-5.

Samples were categorized   as per the IAC diagnostic categories and as forma by the IAC is feasible and the treatment recommendations are appropriate.

1. Naylor B. Pleural, Peritoneal and Pericardial Fluids in Comprehensive Cytopathology. 3rd ed. Bibbo M, editor. Philadelphia: WB Saunders Co.; 2008. p. 515 77
2. Bales CE, Durfee GR. Cytological techniques. In: Koss LG, editor. Diagnostic Cytology and its Histopathologic Bases. 4th ed. Philadelphia: JB Lippincott Company; 1992. p. 1451 531
3. Gulia M, Gulia SP, Mittal SS, Rana S, Tathagat, Aaryan.Reporting of serous effusions in accordance with Indian Academy of Cytology guidelines in a tertiary care centre:a 1-year study.Int J Res Med Sci 2024;12:2318-22.
4. Jha S, Sethy M, Adhya AK. Application of the Indian academy of    cytologists    recommendations    for reporting   serous   fluid   cytopathology   in   routine reporting of ascitic fluid specimen and assessment of the risk of malignancy. J Cytol. 2022;39:72‐7.
5. Kalita DJ,   Thakuria      Indian   Academy   Of Cytology   (IAC)   Grading   For   Reporting   Serous Effusions In A Tertiary Care Hospital Of North East India:  A Three-Year Cross-Sectional Study.  IJAR. 2023;13(12):10-2.
6. Kundu R,  Srinivasan  R,  Dey  P,  Gupta  N,  Gupta  P, Rohilla  M,  et    Application  of  Indian  academy  of cytologists guidelines for reporting serous effusions: An institutional experience. J Cytol. 2021;38:1‐7.