Fluid Analysis:- Part 2 – Fluid Analysis Parameters, Therapeutic Fluid Aspiration
Fluid Analysis
Sample for Fluid Analysis
- The fluid for the analysis are:
- Ascitic fluid.
- Pleural fluid.
- Pericardial fluid.
- Amniotic fluid.
- Cerebrospinal fluid.
- Semen analysis.
- Cervical mucus test.
- Joint fluid (synovial fluid).
- Sweat chloride test.
- Urine analysis.
Indications for Fluid Analysis
- To diagnose the cause of the fluids.
- This could be therapeutic.
- To diagnose the diseases.
Precautions for Fluid Analysis
- The fluid analysis should be done immediately to prevent false results due to cellular or chemical deterioration.
- Follow precautions if there is a delay in the testing of fluid.
Pathophysiology of Fluids
- Effusions from the abdomen, pleura, pericardium, and joints are classified into exudate and transudate.
- Exudates are caused by inflammatory, infectious, or neoplastic diseases.
- Transudates are caused by venous congestion, hypoproteinemia, and fluid overload.
- Some of the fluids are analyzed to diagnose the disease, like sweat for cystic fibrosis.
Various Procedures to get fluids are:
- Lumbar puncture for CSF.
- Amniocentesis to get fluid from the uterus.
- Pericardiocentesis for pericardial fluid.
- Thoracentesis for pleural fluid.
- Paracentesis for the peritoneal fluid.
- Arthrocentesis for the fluid from the joints.
The fluid analysis includes:
- Gross appearance.
- Specific gravity
- Total protein
- LDH level.
- Total cell count.
- Microscopic examination for the differential count.
- Cytospin For the cytological examination.
- In the case of CSF, the glucose level is estimated.
- In some cases, AFB or Gram stain is done.
- Fluid analysis is to diagnose the etiology of fluid formation, or sometimes it may be therapeutic.
Therapeutic advantages of Fluid Analysis:
- Fluid aspirated from the pleural improves ventilation and oxygenation.
- Fluid from the Peritoneum relieves the pressure and ease of breathing and eating.
- Fluid aspirated from the joint relieves the pain and function.
- Fluid aspirated from the pericardial cavity improves diastolic filling and cardiac output.
Difference between various fluids:
Test | Exudate | Transudate | Chylous |
---|---|---|---|
Appearance | cloudy | clear | cloudy to milky |
Color | variable | pale yellow | pale yellow to milky |
Cell count | >1000 | <1000 | >1000 |
DLC | poly → MN cell | lympho | poly → MN cells |
Triglycerides | <60 mg/dL | <60 mg/dL | >110 mg/dL |
Total protein | >3.0g/dL | <3.0g/dL | >3.0g/dL |
Fluid protein/serum TP | >0.5 | <0.5 | >o.5 |
Fluid LDH/serum LDH | >0.6 | <0.6 | >0.6 |
TP = Total protein
MN = Mononuclear cells.
Comparison of Transudate and Exudate:
Parameter (Characteristic features) | Transudate | Exudate |
Appearance | Pale yellow |
Yellow (inflammatory) Red (hemorrhage) Brown (bilirubin) or cloudy |
Protein | <3 g/dL | >3 g/dL |
Fluid: serum protein ratio | <0.5 | >0.5 |
Fluid: LD ratio | <0.6 | >0.6 |
Specific gravity | <1.016 | >1.016 |
WBC | Absent | Increased |
LDH | Normal <200 IU/L | Increased >200 IU/L |
Glucose | Normal (equal to serum level) | Less 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 |
WBCs | Few lymphocytes | Many polys >25% |
RBCs | Few | Variable |
Differential | Mononuclear cells predominate <25% neutrophils |
>25% neutrophils |
- Please see more details in fluid part 3.