Table 2. Comparing frequencies for TPMT deficiency and costs per identified TPMT-deficient individual in the UK and Spain.
| Country/Site | Method | Period | No. of tests | TPMT deficiency rate | Cost per sample | Average cost per identified TPMT-deficient individuala |
|---|---|---|---|---|---|---|
| UK | ||||||
| Guy's Hospital, London | Phenotyping/MS | January 2006–December 2006 | 10 931 | 1:275 | £30 | £8250 |
| City Hospital, Birmingham | Phenotyping/HPLC | April 2006–April 2007 | 11 167 | 1:169 | £28 | £4732 |
| UK combined (both locations) | 22 098 | 1:201 | £29 | £5829 | ||
| Spain | ||||||
| UCB Pharma | Phenotyping/HPLC | January 2006–December 2006 | 5372 | 1:200b | €40 | €8000 |
Abbreviations: HPLC, high-performance liquid chromatography; MS, tandem mass spectrometry, TPMT, thiopurine S-methyltransferase.
a
Figures are shown and calculated only for TPMT-deficient individuals and do not include those with intermediate TPMT values (apparently those being heterozygous for TPMT) who may also be at higher risk for AZA-related adverse events.
b
Figures on TPMT deficiency in Spain are estimated from Gisbert et al.24