| 91249 | S65CMutation (Hemochromatosis) |
| 2044 | Salicylate |
| 91295 | Salmonella |
| 91202 | Saturated Very Long Fatty Acid |
| 2369 | SCL-70 |
| 2369 | Scleroderma Ab |
| 3105 | Sedimentation Rate |
| 3641 | Semen Analysis, Complete |
| 3645 | Semen Count, Qual |
| 91203 | Sensory Neuropathy Antibody Panel |
| 91204 | Serotonin, Whole Blood |
| 1010 | Serum glutamic-oxaloacetic transaminase |
| 2046 | Serum glutamic-pyruvic transaminase |
| 5024 | Sex HB Globulin |
| 5024 | Sex Hormone Binding Globulin |
| 1010 | SGOT |
| 2046 | SGPT |
| 91121 | Sickle Cell Screen |
| 91449 | Single Stranded DNA, Antibody, IgG |
| 91270 | Sirolimus |
| 2371 | Sjogren Antibodies |
| 2349 | Smooth Muscle Ab |
| 1026 | Sodium, Serum or Plasma |
| 1104 | Sodium, Urine Quant |
| 91207 | Somatostatin |
| 2075 | SPEP |
| 3641 | Sperm Count, Complete |
| 3645 | Sperm Count, Qual |
| 4045 | Sputum Culture |
| 2371 | SSA |
| 2371 | SSB |
| 91449 | ssDNA Antibody, IgG |
| 91208 | Stone Analysis |
| 91148 | Stone Risk Assessment |
| 4060 | Stool Culture |
| 3765 | Stool Occult Blood Test |
| 4012 | Strep Culture |
| 4055 | Strep Group A, Rapid w/Reflex |
| 4014 | Strep Group A, Rapid [Without Reflex] |
| 4017 | Strep, Group B Culture |
| 2315 | Streptolysin O Antibody (ASO) |
| 2334 | Streptozyme |
| 3685 | Synovial Fluid Panel |
| 1033 | Syphilis |
| 2628 | Syphilis Antibody, IgG |