. 2014 Feb;35(1):37–61.

Table 3.

Anion gap Monte Carlo simulation. Excel spreadsheet representation showing 10,000 anion gap trials (column H) for the quantity values and uncertainty estimates described in Table 2.

	A	B	C	D	E	F	G	H

1	Input quantities					Formula		Output quantity

2		Na⁺ mmol/L	K⁺ mmol/L	Cl⁻ mmol/L	HCO₃⁻ mmol/L			AG mmol/L
3	Value	140	4.5	105	25	AG = Na⁺ + K⁺ − Cl⁻ − HCO₃	→	14.5
4	Uncertainty	1.2	0.10	1.5	1.2
5		↓	↓	↓	↓
6								Trial results
7	Trial #							AG
8	1	140.12	4.53	105.99	24.16	AG = Na⁺ + K⁺ − Cl⁻ − HCO3⁻	→	14.50
9	2	140.70	4.39	105.44	24.38		→	15.27
10	3	140.16	4.52	104.46	25.70		→	14.51
11	4	140.52	4.59	104.92	24.40		→	15.79
12	5	140.94	4.36	106.54	26.09		→	12.67
13	6	139.05	4.64	105.54	25.18		→	12.97
14	7	139.51	4.58	104.02	24.92		→	15.15
15	8	138.01	4.55	105.05	25.14		→	12.38
16	9	139.94	4.60	102.73	24.50		→	17.31
17	10	140.58	4.47	108.03	23.62		→	13.39
↓	↓	↓	↓	↓	↓		↓	↓
10007	10000	142.73	4.49	107.31	24.97	AG = Na⁺ + K⁺ − Cl⁻ − HCO₃⁻	→	14.94

The simulated anion gap (AG) values in column H are derived from the input variables in columns B, C, D and E, rows 8 to 10007:

Column B rows 8 to 10007; (NORMINV(RAND(),$B$3,$B$4)),
Column C rows 8 to 10007; (NORMINV(RAND(),$C$3,$C$4)),
Column D rows 8 to 10007; (NORMINV(RAND(),$D$3,$D$4)),
Column E rows 8 to 10007; (NORMINV(RAND(),$E$3,$E$4)).

(The arrows (↓ and →) play no part in the calculations; they have been added to the table for illustrative purposes only.)