| MAL | Rapid Malaria/Babesia Smear, Varies Mayo Clinic Laboratories in Rochester | 
      
        | M29 | Rapid Strep Antigen Test Mercy DV, MQMA, MA East and West | 
      
        | REDT | Red Top, IgE, Serum Mayo Clinic Laboratories in Rochester | 
      
        | UREDF | Reducing Substance, Feces Mayo Clinic Laboratories in Rochester | 
      
        | 203 | Renal Function Panel Mercy DBQ, MA East and West | 
      
        | 203R | Renal Function Panel with Reflex to Hemoglobin A1C Mercy DBQ | 
      
        | PRA | Renin Activity, Plasma Mayo Clinic Laboratories in Rochester | 
      
        | RTSC | Reptilase Time, Plasma Mayo Clinic Laboratories in Rochester | 
      
        | RESPCOVID | Respiratory Panel with SARS-CoV-2 PCR Mercy DBQ, Microbiology | 
      
        | RPR8 | Respiratory Profile, Region 8, Central Midwest (IA, IL, MO), Serum Mayo Clinic Laboratories in Rochester | 
      
        | 402 | Respiratory Syncytial Virus (RSV) MQMA, MA East and West | 
      
        | 010 | Reticulocyte Count Mercy DBQ, MA East and West | 
      
        | 062 | Rh Immune Globulin Product Mercy DBQ, MMC DV | 
      
        | 059 | Rh Immune Globulin Workup (Inpatient) Mercy DBQ | 
      
        | 199 | Rh(D) Type Mercy DBQ, Mercy DV, MA West | 
      
        | RF | Rheumatoid Factor Mercy Dubuque | 
      
        | 420 | Rheumatoid Factor, QL MA East and West | 
      
        | RHUT | Rheumatoid Factor, Serum Mayo Clinic Laboratories in Rochester | 
      
        | VITB2 | Riboflavin (Vitamin B2), Plasma Mayo Clinic Laboratories in Rochester | 
      
        | RIBOP | Ribosomal P Antibody Mercy Dubuque | 
      
        | RICE | Rice, IgE, Serum Mayo Clinic Laboratories in Rochester | 
      
        | RNP | RNP Antibody Mercy Dubuque | 
      
        | M62 | Rotavirus Mercy DBQ | 
      
        | MARS | Rough Marsh Elder, IgE, Serum Mayo Clinic Laboratories in Rochester | 
      
        | RRRP | Rough Pigweed, IgE, Serum Mayo Clinic Laboratories in Rochester |