| Screening Test |
Polymorphisms
Represented |
Pertinent Pharmaceuticals Represented |
Limitations |
| Roche CYP2D6/2C19 AmpliChipÒ |
33 CYP2D6 and 2 CYP19 distinct alleles |
25% of known pharmaceuticals [28]. |
Only represents 25% of known CYP2D6 and only 5.5% of known CYP2C19 polymorphisms. |
| Affymetrix Drug Metabolizing Enzyme and Transporters (DMET) |
225 genes involved in drug absorption, distribution, metabolism, and elimination. |
Virtually all pharmaceuticals may be affected by polymorphisms one of these enzymes. |
It is unclear how to clinically interpret this matrix output. |
| HLA-B 5701 |
HLA-B*5701 |
Presence of this polymorphism is associated with 47% PPV and 99% NPV of Abacavir hypersensitivity [17] |
Poor PPV (due to low prevalence of polymorphism) may inappropriately exclude therapy from some patients. |
| Genelex CYP2C9 and VKORC |
CYP2C9*1, *2, *3 and VKORC1 -1639 |
Warfarin dosing [18] |
Screening explains only approx 40% of dosing variation [84]. |
| HLA-B*1502 |
HLA-B*1502 |
Carbamazepine associated Stevens-Johnson Syndrome or toxic epidermal necrolysis in Asian populations [85]. |
Limited to patients of Asian decent. |
| HLA-A*3101 |
HLA-A*3101 |
Carbamazepine associated hypersensitivity reactions in European populations [78]. |
NNT equals 39 European patients, 56 Japanese patients and 83 patients of un-determined decent. |
| HER2
(INFORM® HER2 FISH test, PathVysion® HER2 FISH test, PharmaDX® HER2 FISH test, Spot-Light® HER2 CISH test) |
Number HER2 gene copies |
Herceptin efficacy in breast [86] and gastric [86] cancer. |
Equivocal results should be confirmed by a second screening method. 4 FDA approved genetic methods available. |
| CYP2C19 |
CYP2C19 metabolizer status |
Poor metabolizers do not form active metabolite of clopidogrel 25]. |
Improved outcomes have been demonstrated in Chinese patients [30] only and no major society recommends genotyping prior to therapy to date. |
| G6PD |
G6PD mutation by semi-quantitative or spectrophotometric methods [64] |
High risk of hemolysis in patients receiving dapsone, methylene blue, nitrofurantoin, phenazopyridine, primaquine, rasburicase, and toluidine blue [87]. |
Initial semi-quantitative analysis should be confirmed by spectrophotometric method due to wide variability of enzyme function. |
PPV: positive predictive value
