Fluid Analysis:- Part 1 – Body Fluids and Their Importance, Transudate and Exudate

February 6, 2024Fluid analysis Lab Tests

Table of Contents

Fluid Analysis

How will you define Fluids in various cavities of the body?

The fluid is secreted by the serous membranes lining the peritoneum, pleural and pericardial cavities.
Literally, serous fluid means resembling serum.

What is the importance of fluid in the various cavities?

This serous fluid is found in the pleural, peritoneal, and pericardial cavities, which will lubricate the opposing parietal and visceral membrane surfaces.
Inflammation or infection affecting the cavities causes fluid to accumulate.
Serous fluid is the ultrafiltrate of the plasma.
The fluid formation depends upon the following:
1. Hydrostatic pressure.
2. Capillaries permeability.
3. Colloid osmotic pressure.
4. Lymphatic drainage.

What are the types of body fluid and their normal quantity?

The pericardial cavity around the heart contains the fluid, and the aspiration of the pericardial fluid is called pericardiocentesis.
1. Normal pericardial fluid is 15 to 50 mL.
Peritoneal or ascitic fluid is found in the abdomen. This is the effusion and accumulation of serous fluid in the abdominal cavity. Its aspiration is called paracentesis.
1. Normal peritoneal fluid is 50 to 75 mL.
Pleural cavity fluid was found in the chest. Aspiration is called thoracentesis.
1. Normal pleural fluid is 10 to 20 mL.
Gastric fluid is 1000 to 3000 mL/day.
Bile is 300 to 1000 mL/day.
Saliva is 500 to 1500 mL/day.
Pancreatic fluid is 1000 to 1500 mL/day.
Small intestinal fluid is 1000 to 2000 mL/day.
Urine output is 500 to 1500 mL/day.
Insensible loss through skin and lungs is 600 to 1000 mL/day.

Normal Body Fluids at various sites

What are Normal Various body fluids and their quantities?

Fluid site	Quantity Produced
Saliva	500 to 1500 ml/day
Gastric fluid	1000 to 3000 mL/day
Pancreatic fluid	1000 to 1500 mL/day
Small intestinal fluid	1000 to 2000 mL/day
Bile	300 to 1000 mL/day
Urine output	500 to 1500 mL/day
Loss from the skin and lungs	600 to 1000 mL/day
Synovial fluid	Minimal amount, Knee Joint <29 mL
Cerebrospinal fluid	Total volume = 90 to 200 mL
Ascitic fluid, pericardial, and pleural fluids	These are always abnormal collection
Insensible loss through skin and lungs	600 to 1000 mL/day

What are the normal findings of serous fluids?

Parameters	Characteristic features
Appearance	Usually pale yellow It may be clear It has a low viscosity Turbidity indicates increased leucocytes Red or pink is due to blood
pH	6.8 to 7.6
Specific gravity	1.010 to 1.025
Total protein	1000 to 2000 mg/dL
Globulin	30% to 45%
Albumin	50% to 70%
LDH	Increased due to necrosis and dead leucocytes

What are the normal Ascitic fluid findings?

Parameters	Characteristic features
Gross appearance	It is a clear, serous, and light yellow
Protein	<4.1 g/dL
Glucose	70 to 100 mg/dL
Amylase	138 to 404 units/L
Alkaline phosphatase	Adult male = 90 to 240 units/L Female <45 years = 76 to 196 units/L Female >45 years = 87 to 250 units/L
LDH	Like serum LDH level
CEA	Negative
Presence of cells	RBC = none WBCs = <300 /cmm
Bacteria	Negative
Fungus	Negative
Cytology	Negative for malignant cells

Transudate

What are the characteristic features of Transudate?

What is the mechanism of transudate formation?

It is the fluid that accumulates as ultrafiltrate and is called Transudate.
The capillary pore can allow the passing of the protein of mol. Weight of 200,000 to 300,000 daltons.
The larger molecular weight proteins are held back and can not cross the basement membranes.
Transudate accumulates because of the increased hydrostatic pressure in the capillaries.
The fluid is low in protein as compared to plasma.

Transudate mechanism

What are the features of Transudate?

Parameters	Values
Specific gravity	1.016
Protein	<3 g/dL
White blood cells	Negative
Glucose	Normal
LDH	Normal

Exudate

What are the characteristic features of Exudate?

What is the mechanism of exudate formation?

Fluid accumulates because of the injury to the membranes due to infection or inflammation.
The damaged membranes allow passing through the larger molecules of proteins.

Exudate mechanism

What are the features of Exudate?

Parameters	Values/Findings
Specific gravity	>1.016
Proteins	>3 g/dL
White blood cells	Increased in number
Glucose	It is decreased
LDH	It is increased

What are the types of exudates?

Serous.
Fibrinous.
Serofibrinous.
Purulent.
Putrid.
Chylous.
Serosanguinopurulent.

How will you Differentiate between Transudate and Exudate?

Parameter	Transudate	Exudate
Appearance	Pale yellow No turbidity	Yellow = inflammatory Red = hemorrhage Brown = bilirubin Turbid, viscous, cloudy
Protein	<3 g/dL	>3 g/dL
Fluid protein: serum protein ratio	<0.5	>0.5
Fluid LD: Serum LD ratio	<0.6	>0.6
Specific gravity	<1.016 (<1.015)	>1.016 (>1.015)
WBC	Absent	Increased
LDH	Normal <200 IU/L	Increased >200 IU/L
Glucose	Normal (equal to serum level)	<than or equal to serum
Pleural fluid cholesterol	<60 mg/dL	>60 mg/dL
Pleural fluid: serum cholesterol ratio	<0.3	>0.3
Pleural fluid: bilirubin ratio	<0.6	>0.6
Fibrinogen	No clot	Clots are seen
Spontaneous clotting	Negative	May see clot formation
Cell count	300 to 1000 /cmm	>1000 /cmm
Differential	Mononuclear cells predominate <25% neutrophils	>25% neutrophils

Fluid Analysis: Fluid exudate/transudate

Questions and answers:

Question 1: What is protein level in transudate?

Show answer

Question 2: What is the cell count in the exudate?