| Business | Phone |
| American Drug Screening Svc 635 W 19th St, Houston 77008 | (713) 869-8378 |
| National Screening Ctr 412 Main St, Houston 77002 | (713) 226-7847 |
| Beacon Drug Testing 11500 Northwest Fwy, Houston 77092 | (713) 957-0084 |
| Disa Inc 10750 Hammerly Blvd, Houston 77043 | (713) 972-3472 |
| Discount Auto Sales & Svc 9607 Linkmeadow Ln, Houston 77025 | (713) 838-0200 |
| Drug Testing & Background 14133 Memorial Dr, Houston 77079 | (281) 597-1611 |
| Medical Profiles Inc 2539 S Gessner Rd 24, Houston 77063 | (832) 251-3926 |
| Global Medical Testing 2636 South Loop W 225, Houston 77054 | (713) 662-3300 |
| Med-Tech Inc 8830 Long Point Rd, Houston 77055 | (713) 932-7800 |
| Houston Medical Testing Svc 2646 South Loop W 550, Houston 77054 | (713) 665-4687 |
| Inter Fit Health Svc 9 E Greenway Plz, Houston 77046 | (713) 935-0333 |
| Interquest Group Inc 21900 State Highway 249, Houston 77070 | (281) 320-1231 |
| Mro Svc Inc 2525 W Bellfort St, Houston 77054 | (713) 838-0200 |