Thread by @kidney_boy

Michael Emmett on electrolyte artifacts
Pre-analytical and analytical #NKFClinicals

Starting with pseudohyponatremia
These are real cases
The osmolality was 294, so there is a huge gap. 44ish
Implies Artifactual decrease in sodium
Her triglycerides were >6000 #NKFClinicals

Note the different between HCO3 and tCO2 should be closer than 19 and 9. #NKFClinicals

The Flame photometer created the specialty of nephrology by allowing rapid measurement of Na and K. Calls it the engine of nephrology. Took time of measuring Na from all day to minutes. #NKFClinicals

When we talk liters we are usually talking about liters of serum/plasma, but we measure concentrations in liter of water. If that solid component goes from 7% to 20% you over dilute the sample. Solid is usually lipid, could also be protein. #NKFClinicals

The next innovation was the ion selective electrode and it did not have this weakness #NKFClinicals

Now we use indirect ion selective electrode reintroduces the dilution step which re-introduces the error which we avoided with direct ion selective electrode. #NKFClinicals

Conclusion #NKFClinicals

The bicarbonate is dropped by the lipids due to the inability to transmit light through the sample. Hyperviscosity also results in overdilution.

Nice study showing the relationship to Na error to protein concentration #NKFClinicals

Severe cholestasasis can increase Lipoprotein X no lipemic blood. After BMT and liver failure. #NKFClinicals

Anion gap of minus 47.
They checked bromide levels. Which were normal.
What is the cause of pseudo hyper chlorine? #NKFClinicals

Chloride sensitive electrodes can be poisoned by aspirin causing increased permeability of the electrode. #NKFClinicals