TABLE 2.

Serum vitamin B₁₂ levels and absorption test (by Schilling test) and folate levels before and after restorative proctocolectomy (RPC)

Point of control	Parameter	n	% below normal vs. ref value	% above normal vs. ref value	Mean ± SEM	P value vs. precolectomy	Reference level
Precolectomy	Vitamin B12	41	8	10	433 ± 31.45 pmol/L		40–840 pmol/L
Ileostomy	Vitamin B12	43	7	2	353 ± 32.27 pmol/L	0.17
Loop ileostomy	Vitamin B12	61	8	3	326 ± 30.78 pmol/L	0.28
6 months	Vitamin B12	69	7	3	335 ± 26.81 pmol/L	0.33
12 months	Vitamin B12	58	3	5	349 ± 27.73 pmol/L	0.19
18 months	Vitamin B12	53	6	2	319 ± 23.24 pmol/L	0.03
24 months	Vitamin B12	51	6	4	380 ± 36.1 pmol/L	0.50
36 months	Vitamin B12	28	11	0	350 ± 27.22 pmol/L	0.09
Precolectomy	Schl-with-IF	16	38	12	17 ± 2.48 %		12–30% with IF
	Schl-without-IF	17	35	12	16 ± 2.41 %		11–28% without IF
12 months	Schl-with-IF	67	30	6	16 ± 1.09 %	0.87
	Schl-without-IF	67	31	6	15 ± 0.99 %	0.42
36 months	Schl-with-IF	35	37	0	15 ± 1.22 %	0.23
	Schl-without-IF	36	36	0	15 ± 1.23 %	0.13
Precolectomy	Folate	42	12	0	14.99 ± 1.83 nmol/L		>4nmol/L
Ileostomy	Folate	43	0	0	16.16 ± 1.71 nmol/L	0.01
Loop ileostomy	Folate	61	0	0	16.78 ± 1.76 nmol/L	0.01
6 months	Folate	66	0	0	16.20 ± 1.13 nmol/L	0.01
12 months	Folate	56	0	0	16.10 ± 1.40 nmol/L	0.002
18 months	Folate	51	0	0	16.90 ± 1.67 nmol/L	0.001
24 months	Folate	44	0	0	16.51 ± 1.77 nmol/L	0.005
36 months	Folate	25	0	0	19.22 ± 2.44 nmol/L	0.001

Precolectomy, levels the night prior to total colectomy and ileostomy; Ileostomy, levels night prior to pouch construction; Loop ileostomy, levels prior to closure of diverting loop ileostomy; months, levels of functional pouch after diverting loop ileostomy closure; IF, intrinsic factor (vitamin B₁₂ intrinsic factor).

Adapted and published (2001) with permission from the Karolinska Institue database.³⁶