% haemolysis using hematocrit

[pretzal]

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All the equations I've found to calculate %hemolysis are as follows:

[supernatant Hb x (100- Hct)]/ total Hb

rather than simply (supernatant Hb/ total Hb) x100

But my question is, what exactly is the 100-hematocrit part actually correcting for?

Thanks!

 

[Damocles]

It is the conversion factor from dL plasma to dL blood, so that % hemolysis comes out unitless:

(g Hb/dL plasma) X (100-Hct)(dL plasma/dL blood) X (dL blood/gHb)

supernatant hemoglobin and total hemoglobin are not being measured in the same sample.

 

[pretzal]

Thanks for your response!

I think I get it now, so basically 1-Hct gives the fraction of plasma in the blood sample, and it's this fraction that is multiplied with the plasma concentration so that the volume (and therefore the concentration) is adjusted to match that in the blood sample? Let me know if I've understood you right 🙂

Again, thanks for the help, was bugging me for ages!

 

[Damocles]

Yes, I think you've got it. Supernatant Hb and total Hb in your formula are both concentrations (g/dL), not mass (g), so you need to throw in the conversion factor. You end up calculating (g Hb supernatant)/(g Hb total) in a specified volume of blood, which is what you want.