Lab Case 7 – Interpretation


1. Renal Function

Urea 22.2, Creatinine 758, eGFR 4 – consistent with severe acute renal failure.

Urea:Creat = 34

ratio of less than 40 implies likely renal cause, check UA for granular casts, tubular epithelial cells.

You would expect hyperK, however in this case there is moderate to severe hypoK (see previous post for implications) and metabolic acidosis (high AG)

Mg 0.71 – will require replacement in order to correct low Potassium.

2. HCO3 = 29, implying metabolic alkalosis. In addition there is hypoCl and hypoK.

The kidneys can usually rapidly excrete HCO3, so maintenance of metabolic alkalosis requires an underlying disease process.

Causes include

Vomiting – loss of HCl acid

Diuretics (Frusemide/ thiazides) – interefere with Cl/ Na reabsorption in renal tubules, and also cause hypoK

Other causes to consider in this patient (with K depletion) include

Endocrine – Conn’s, Cushings, secondary hyperaldosteronism

RTA type I and II


Barter’s Syndrome

3. Other abnormalities in this patient

High WCC and Neutrophils – ?posssible infection

4. Normal Na, Hb (low normal), Platelets

Implications – this patient requires urgent Potassium replacement (with Magnesium), fluid therapy and admission under the renal team for ongoing renal monitoring and investigation of underlying causes.

Indications for urgent CVVHDF include:

a. severe hypokalaemia (>7)

b. Refractory fluid overload (APO)

c. Severe acidosis (pH <7.2/ BE <-10)

d. Other – Uraemic pericarditis, encephalopathy and drugs that are amenable to dialysis (Li, Salicylates, Na Valproate)