| FOAKE | Oak Live (Quercus virginiana) IgE Eurofins Viracor | 
      
        | FROE | Oak Red (Quercus rubra) IgE Eurofins Viracor | 
      
        | FOATG | Oat IgG Eurofins Viracor | 
      
        | OCT2 | OCT-2 Immunostain, Technical Component Only Mayo Clinic Laboratories in Rochester | 
      
        | OCT4 | OCT3/4 Immunostain, Technical Component Only Mayo Clinic Laboratories in Rochester | 
      
        | OLIG2 | OLIG2 Immunostain, Technical Component Only Mayo Clinic Laboratories in Rochester | 
      
        | OLIGS | Oligoclonal Banding, Serum Mayo Clinic Laboratories in Rochester | 
      
        | OLIGC | Oligoclonal Banding, Spinal Fluid Mayo Clinic Laboratories in Rochester | 
      
        | OLIGU | Oligosaccharide Screen, Random, Urine Mayo Clinic Laboratories in Rochester | 
      
        | FOLBG | Olive Black IgG Eurofins Viracor | 
      
        | FONG | Onion IgG Eurofins Viracor | 
      
        | FCDU1 | Opiates, Umbilical Cord Tissue NMS Labs | 
      
        | FORNG | Orange IgG Eurofins Viracor | 
      
        | FORGG | Oregano IgG Eurofins Viracor | 
      
        | ORXNA | Orexin-A/Hypocretin-1, Spinal Fluid Mayo Clinic Laboratories in Rochester | 
      
        | OAUS | Organic Acids Screen, Urine Spot Mayo Clinic Laboratories in Rochester | 
      
        | FORRT | Orris Root (Iris florentina) IgE Eurofins Viracor | 
      
        | OTP | Orthopedia Homeobox Protein (OTP) Immunostain, Technical Component Only Mayo Clinic Laboratories in Rochester | 
      
        | ORTHP | Orthostatic Proteinuria, Random, Urine Mayo Clinic Laboratories in Rochester | 
      
        | OSM24 | Osmolality, 24 Hour, Urine Mayo Clinic Laboratories in Rochester | 
      
        | OSMOF | Osmolality, Feces Mayo Clinic Laboratories in Rochester | 
      
        | OSG_F | Osmotic Gap, Feces Mayo Clinic Laboratories in Rochester | 
      
        | OIBFG | Osteogenesis Imperfecta and Bone Fragility Gene Panel, Varies Mayo Clinic Laboratories in Rochester | 
      
        | OAPNS | Ova and Parasite, Microscopy, Varies Mayo Clinic Laboratories in Rochester | 
      
        | OPE | Ova and Parasite, Travel History or Immunocompromised, Feces Mayo Clinic Laboratories in Rochester |