In a 32yr old male presenting with the following blood chemistry Na+ → 135,K+ → 5.0, HCO3- → 14.0, Cl- → 116, PO4-- →
5.0, S04-- → 5.0, Mg++ → 2.0, Ca++→ 8.0 the anion gap is :
We cannot get the answer by using the calculation we have all been using till now i.e. -
Anion gap =  - 
then the anion gap would be - = 5
But 5 is not an option
In all the books I have looked for i.e., Harrison, Nelson Ganong, Guyton, C.P.D.T., Cecil; anion gap is calculated in
the similar way except for Bailey where anion gap is calculated as follows:
Anion gap =  -  Using this anion gap is
equal to 140 - 130 = 10
20
15
13
10