This document provides information about examining serous fluids, including pleural, pericardial, and ascitic fluids. It discusses the normal formation of serous fluids and how to differentiate transudates from exudates. It outlines various routine tests that can be performed on serous fluids, such as physical examination, microscopic examination including cell counts and differentials, and chemical tests including measurements of protein, glucose, LDH, and others. Approaches to examining different types of serous fluids are also summarized.

1. SEROUS FLUID
EXAMINATION
Dr Shweta Garg
MD Pathology
KGMU Lucknow
CONSULTANT PATHOLOGIST
NUTEMA HOSPITAL, MEERUT.

2. LEARNING OBJECTIVE
• NORMAL FORMATION OF SEROUS FLUID
• DIFFERENTIATE BETWEEN TRANSUDATE AND
EXUDATE
• VARIOUS OTHER ROUTINE & SPECIAL TEST &
THEIR CLINICAL & DIAGNOSTIC SIGNIFICANCE

3. GENERAL CONSIDERATION
• Serous fluids – secreted by serous membrane (Parietal and
visceral), lining the close cavity of body
• These are named as per location
• Pleural
• Pericardial
• Peritoneal
• Their function is to provide lubrication between two
membranes

4. FLUID FORMATION
- These are extravascular fluid
collected in intercellular spaces
(body cavity) and come from
vascular space.
- It is produced by exertion of
hydrostatic pressure and oncotic
pressure and small amount is
absorbed by lypmphatics

5. HOW DOES EFFUSION OCCUR ?
• Increase venous pressure i.e Hydrostatic pressure
• Greater exit of fluid from the vascular system than it is
absorbed
• Capillary permeability does not change
• Fluid resembles like normal tissue fluid – few cells & very low
protein
• Congestive heart failure, salt & fluid retention
• Increase capillary permeability
• Due to inflammation or toxic damage to capillaries –
microbial infection
• Contain high concentration of protein

6. HOW DOES EFFUSION OCCUR ?
• Decrease in plasma colloidal pressure
• In cases of Hypoproteinaemia – like nephrotic Syndrome
• Hepatic cirrhosis
• Malnutrition, Protein losing enteropathy
• Interference with lymphatic flow
• Due to obstruction of lymphatic flow – Filaria, Cancer,
Scar tissue, thoracic duct injury
• Contain high concentration of protein & lipids

7. TRANSUDATE & EXUDATE
• Transudate is fluid buildup caused by systemic conditions
that alter the pressure in blood vessels causing fluid to leave
the vascular system.
• Exudate is fluid build up caused by tissue leakage due to
inflammation or local cellular damage.

9. LIGHT’S CRITERIA
The fluid is exudate if one of the following Light’s criteria is
present:
1. Effusion protein/ serum protein ratio > 0.5
2. Effusion lactate dehydrogenase( LDH) / serum LDH ratio
>0.6
3. Effusion LDH level greater than two thirds the upper limit
of reference range of LDH

10. GENERAL LAB TESTING
• Specimen collection and handling
• Examination of Fluid
• Physical examination
• Microscopic examination
• Chemical examination
• Microbiological and serological test
• Ancillary test

11. SPECIMEN COLLECTION AND HANDLING
• Pleural fluid: Thoracocentesis is indicated for therapeutic
purposes in patients with massive symptomatic effusion.
• Peritoneal fluid: Diagnostic Paracentesis is performed in most
pts of ascites. Min of 30 ml is required.
• Pericardial fluid:
• Sample is obtained by Pericardiocentesis in a wide mouth
universal container.
• Post test the samples are stored at 4-8 ֯C for 48 hours.

13. COLLECTION OF SAMPLE
• To be collected in three tubes
• EDTA for Haematolgy
• Plain for Biochemistry
• Sterile heparinised / Plain for microbiology & Cytology
• It should be examined as early as possible to avoid chemical
change, bacterial growth & cellular disintegration
• Remaining sample can be stored at 2 – 4 C for further
ancillary testing

14. PROCEDURAL STEPS
Physical examination:
• Volume
• Color
• Appearance
• Presence/absence of coagulum
Coagulum formation occurs due to substantial
inflammatory reaction and presence of fibrinogen due to
capillary wall damage

15. MICROSCOPIC EXAMINATION
• Done for routine TLC & DLC and cytological purpose
• For TLC, mix the specimen carefully, if clear, use undiluted.
• If blood- tinged prepare 1:2 dilutions with diluting fluid
• If cloudy, prepare 1:20 dilution with diluting fluid or normal saline
(composition of Turk solution: Glacial acetic acid 4 ml, methylene
blue solution 10 drops, & distilled water to make 200 ml).
• Count the cells in the corner 4 squares of neubauer chamber.

16. • Calculation: TLC/cumm= n ×D/V
where “n”= no. of cells in four corner squares
“D”= dilution factor
“V”= volume (vol. of 4 wbc chamber)

17. NEUBAUER CHAMBER

18. • Now the fluid is centrifuged at 1500 rpm for 5 minutes &
sediment is used to prepare smears for DLC, malignant cell
& cytology.
• Smears are stained with Leishman, Giemsa & PAP stain.
• Limitations: Counts should be performed as soon as
possible.
• Specimen should be stored at 2-8֯ C for 48 hrs

19. FLUID CYTOLOGY

20. Chemical Examination
• Following chemical test are preformed
• Protein & Albumin in some
• Glucose
• LDH
• Others –
• Triglyceride to rule out chylous effusion
• Amylase – to rule out pancreatitis or esophageal rupture
• ADA – helps in making diagnosis of tuberculosis ( Usually >
40 IU/L in tubercular effusion & ascites)

21. APPROACH TO PLEURAL
FLUID EXAMINATION

26. HAEMATOLOGY TEST
• Increase Neutrophil
• Bacterial infection, Pancreatitis, Pulmonary infarction
• Increase Lymphocytes
• Tuberculosis, Viral infection, Autoimmune disorders,
Malignancy
• Increase Eosinophils > 10 %
• Trauma introducing air and blood, allergic reaction,
parasite / fungal infection, pulmonary infarction, Drugs

27. Eosinophilic effusion

30. PERICADIAL FLUID
EXAMINATION

31. PERICADIAL FLUID EXAMINATION
• Normally 10 -50 ml of pericardial fluid
• Straw coloured
• Transudate (Pale yellow, clear) – Hypothyroidism, Uraemia,
Autoimmune disorder
• Exuduative (Turbid ) – Infection , Malignancy
• Haemorrhagic – Trauma, Uraemia, Tubercular
• Milky – Chylous and Pseudochylous

32. PERICADIAL FLUID EXAMINATION
• CHEMICAL EXAMINATION
• Protein – little use
• Glucose < 40 mg/dl in Tuberculosis, bacterial and
Rheumatic diseases and malignancy
• ADA – increase in Tuberculosis
• MICROSCOPY
• WBC > 1000 cells/cu mm in Bacterial infection and TB
• Malignant cell – Metastatic from lung and breast

33. PERICADIAL FLUID
• MICROBIOLOGICAL EXAMINATION
• Gram Stain – positive in 50% bacterial infections
• Culture – Positive in 80% of bacterial infections
• AFB – Positive in 50% of Tubercular cases

35. ASCITIC FLUID
EXAMINATION

36. PERITONEAL FLUID
• Peritoneal cavity normally contain upto 50ml of clear straw
colored fluid
• Patient with peritoneal effusion is said to have ascitis and it
is called ascitic fluid
• The procedure of collecting the ascitic fluid is called
abdominal paracentesis
• Indications: ascites of unknown etiology, acute abdominal
pain, post operative hypotension, intra abdominal
hemorrhage etc
• Specimen collected into tubes same as for other fluid

37. CAUSES OF ASCITES

39. PHYSICAL EXAMINATION
• Colour and appearance: normally clear and pale yellow
• Turbid: appendicitis, pancreatitis etc.
• Green: intestinal perforation, cholecystitis
• Milky: nephrotic syndrome, carcinoma, parasitic infection
• Bloody: hemorrhagic pacreatitis, reptured spleen or liver
• Examine for clot formation

40. MICROSCPIC EXAMINATION
• Total leukocyte useful in spontaneous bacterial peritonitis
(SBP)
• Approximately 90% of (SBP) have leukocyte count
>500/cumm and over 50% neutrophiles
• Increase lymphocyte – Favours TB
• Eosinophilia >10% most commonly associates with CHF,
vasculitis, lymphoma and ruptured hydatid cyst

44. CHEMICAL EXAMINATION
• Estimation of glucose has little value
• Decreased in peritonitis ,malignancy
• Estimation of amylase - Increased in acute pancreatitis,
(more than 3 times of serum values) , Gi perforation
• Estimation of ALP - Elevated in intestinal perforation
• Estimation of LDH – Increase in Malignancy

45. CHEMICAL EXAMINATION
• Estimation Urea and Creatinine – Traumatic rupture of
urinary tract or in renal transplant surgery (ureteric
dehiscence)
• ADA – increase more than 40 unit/liter in TB peritonitis
• Tumour marker
• Presence of CA 125 antigen with a negative CEA suggests
the source is from ovaries, fallopian tube, or
endometrium
• Presence of CEA suggests source is gastrointestinal

46. MICROBIOLOGY TESTS
• Gram stains and aerobic and anaerobic cultures
• Aerobic cultures : inoculate blood culture in blood culture
bottles , sensitivity increases from 50 % to 80% if done with
BACTEC vis a vis conventional
• Acid fast smear , adenosine deaminase and culture for TB

49. THANK YOU

51. Examination of pleural fluid

52. • Ascites • Diagnosis: • established with a combination of a physical
examination & an imaging test (USG). • Approx 1500 mL of fluid had
to be present for flank dullness to be detected • lesser degrees of
ascites can be missed. • Ultrasonography can be helpful when the
physical examination is not definitive

53. • Causes of Ascites • Ascites can be classified based on the underlying
pathophysiology: • Portal hypertension – Cirrhosis – Alcoholic
hepatitis – Acute liver – Hepatic veno-occlusive disease (eg, Budd-
Chiari syndrome) – Heart failure – Constrictive pericarditis –
Hemodialysis-associated ascites (nephrogenic ascites)

54. • Causes of Ascites • Hypoalbuminemia – Nephrotic syndrome –
Protein-losing enteropathy – Severe malnutrition • Peritoneal disease
– Malignant ascites (eg, ovarian cancer, mesothelioma) – Infectious
peritonitis (eg, tuberculosis or fungal infection) – Eosinophilic
gastroenteritis – Starch granulomatous peritonitis – Peritoneal dialysis

55. • Causes of Ascites • Other etiologies – Chylous ascites – Pancreatic
ascites (disrupted pancreatic duct) – Myxedema – Hemoperitoneum

56. • International Ascites Club Grading system • Grade 1 – Mild ascites
detectable only by ultrasound examination • Grade 2 – Moderate
ascites manifested by moderate symmetrical distension of the
abdomen • Grade 3 – Large or gross ascites with marked abdominal
distension

57. • Abdominal Paracentesis • Most efficient way to confirm the presence
of ascites, diagnose its cause, and determine if the fluid is infected. •
Safe procedure, with an extremely low incidence of serious
complications despite the coagulopathy that is usually present in
patients with cirrhosis. • Coagulation parameters beyond which
paracentesis should be avoided. • There are no data-supported
however, patients with clinically evident fibrinolysis or disseminated
intravascular coagulation should not undergo paracentesis.

58. TESTS PERFORMED ON ASCITIC FLUID
• Routine tests
• Cell count and differential
• Albumin concentration
• Total protein concentration
• Culture in blood culture bottles
• Optional tests
• Glucose concentration
• LDH concentration
• Gram stain
• Amylase concentration
• Other tests •
• Tuberculosis smear and culture •
• Cytology •
• Triglyceride concentration •
• Bilirubin concentration

60. • Cell count and differential • The cell count with differential is the
single most helpful test performed on ascitic fluid to evaluate for
infection. • Polymorphonuclear count ≥ 250/mm3 – spontaneous
bacterial peritonitis. • In bloody ascites: – one neutrophil should be
subtracted from the absolute neutrophil count for every 250 red cells
to yield the "corrected neutrophil count“

61. SERUM-TO-ASCITES ALBUMIN GRADIENT
• • The serum-to-ascites albumin gradient (SAAG) accurately identifies
the presence of portal hypertension and is more useful than the
proteinbased exudate/transudate concept. • SAAG – serum albumin
value - ascitic fluid albumin – (obtained on the same day). • SAAG ≥
1.1 g/dL (11 g/L) – Indicates portal hypertension – (Budd-Chiari
syndrome, heart failure, or liver cirrhosis) • SAAG

62. • Sending Cultures • Bacterial cultures of ascitic fluid should be sent
from patients with – new onset ascites • admitted with ascites • Who
deteriorate with – Fever, – Abdominal pain – Azotemia, – Acidosis –
confusion

63. • Protein, Glucose, LDH • Protein — Ascitic fluid had been classified as
an exudate if the total protein concentration is ≥2.5 or 3 g/dL and a
transudate if it is below this cut-off. However, the exudate/transudate
system of ascitic fluid classification has been replaced by the SAAG. •
Measurement of total protein, glucose, and lactate dehydrogenase
(LDH) in ascites may also be of value in distinguishing SBP from gut
perforation into ascites • Patients with ascitic fluid that has a
neutrophil count ≥250 cells/mm3 and meets two out of the following
three criteria are unlikely to have SBP and warrant immediate
evaluation to determine if gut perforation into ascites has occurred. –
Total protein >1 g/dL – Glucose

64. TESTS FOR TUBERCULOUS PERITONITIS
• Direct smear - 0 to 2% sensitivity in detecting Mycobacteria
• Culture - When one litre of fluid is cultured, sensitivity for
Mycobacteria 62 to 83%
• Fluid for PCR for tuberculosis
• Cell count - Tuberculous peritonitis can mimic the culture-negative
variant of SBP, but lymphocyte cells usually predominate in
tuberculosis
• Adenosine deaminase
• Adenosine deaminase activity of ascitic fluid has been proposed as a
useful non-culture method of detecting tuberculous peritonitis;
however, patients with cirrhosis and tuberculous peritonitis usually
have falsely low values .