(PYQ: INICET Nov 2024)
|
Compartment |
% of Body Weight |
Indicators Used |
|
Total Body Water (TBW) |
~60% |
• D₂O (Deuterium oxide / Heavy water) • ³H₂O (Tritiated water) • Antipyrine • Aminopyrine |
|
Extracellular Fluid (ECF) |
~20% |
• Inulin (Best) • Mannitol • Sucrose • Thiosulfate • Radioactive sodium |
|
Plasma Volume (ECF - PV) |
~5% |
• Evans blue (T-1824) • ¹²⁵I-albumin (Radioactive iodine labelled albumin) |
NOTE: Interstitial fluid volume and intra cellular fluid volume can’t measured directly but are instead calculated indirectly.
1. Interstitial fluid volume = Extra cellular fluid volume - Plasma volume
2. Intra cellular fluid volume = Total body water - Extra cellular fluid volume