| Test | Specimen Requirements |
| Largactil (Chlorpromazine)* | 10 mL GEL (white / yellow). |
| LDH (Lactate Dehydrogenase) | 10 mL GEL (white / yellow). |
| Lead (Pb)* Red Cell Urine | 4mL EDTA (purple). 24 hr urine collection in acid washed bottle or spot urine |
| Legionella Antibodies* Total Ab | 10 mL GEL (white / yellow). |
| Leptospirosis* IgM | 10 mL GEL (white / yellow), May need convalescent specimen |
| LH (Luteinizing Hormone) | 10 mL GEL (white / yellow). |
| Librium (Chlordiazeposide)* | 10 mL GEL (white / yellow). State time / date of last dose & time / date of collection. |
| Lipase | 10 mL GEL (white / yellow) |
| Lipoprotein Electrophoresis* Alpha Pre Beta Beta | 10 mL GEL (white / yellow). |
| Lithium* | 10 mL GEL (white / yellow). Sample Time: Pre-Dose. State time / date of last dose & time / date of collection. |
| Lupus Anticoagulant Factor APTT, KCT & dRVVT | 2 x 4ml SODIUM CITRATE (blue). Double spin, separate plasma & freeze |
| Lupus Screen (ANF) Anti-nuclear factor | 10 mL GEL (white / yellow). |
| Lyme Disease* IgG and IgM | 10 mL GEL (white / yellow). |
| Lymphocyte Surface Markers (LSM)* | 4 mL EDTA (purple). Performed by IMR. (BY APPT. ONLY) |
| LKM Autoantibodies (Liver, Kidney, Muscle)* | 10 mL GEL (white / yellow). |
| Lp (a) (Lipoprotein a) | 10 mL GEL (white / yellow). |