Table 4

Red blood cell (RBC) 6-thioguanine nucleotide (6-TGN) concentrations

Patient group	No patients	6-TGN (pmol/8×10⁸ RBCs)
All patients		170	Median 136
			Mean (SD) 163 (99)
			Range 12–564
Intermediate range TPMT activity^4-150		23	Median 282
			Mean (SD) 253 (136)
High range TPMT activity^4-150		141	Median 130
			Mean (SD) 151 (84)^4-160
Patients with active disease (IBDQ <170)		56	Median 139
			Mean (SD) 178 (116)
Patients in clinical remission (IBDQ ⩾170)		114	Median 131
			Mean (SD) 156 (89)

↵4-150 Six patients did not undergo TPMT testing.
↵4-160 Patients with intermediate TPMT activity levels were more likely to have high whole blood 6-TGN concentrations (p=0.002).
IBDQ, inflammatory bowel disease questionnaire.