Kokilaben Hospital's Department of Laboratory Medicine is the largest in Mumbai and is housed on a single floor spread over more than 40,000 sq. ft. The laboratory offers over 3,000 routine and highly advanced diagnostic, genetic and molecular biology tests. The services offered by the lab include Biochemistry, Haematology, Histopathology, Microbiology, Clinical Pathology, Transfusion Medicine, Blood Bank, Genetics and Molecular Biology. Subspecialties include molecular genetics, cytogenesis, genetic counselling, predictive tests for cancer and heart disease plus a complete screening programme for infertility, miscarriage and prenatal diseases.

The hospital blood bank, an independent service, has introduced Component Therapy. Blood taken from a healthy donor can be separated into its component parts, where the needed component is collected and the unused components are returned to the donor. Component therapy includes Plasmapheresis, which is useful in collecting Fresh Frozen Plasma (FFP); Plateletpheresis, the collection of platelets; Leukapheresis, the removal of white cells, for transfusion into patients; and Stem Cell Harvesting, where circulating bone marrow cells are harvested to use in bone marrow transplantation.

The lab, which is supported by expert doctors and technicians, provides laboratory testing for all the inpatients and outpatients. It works on a hospital-wide information system for ordering and reporting laboratory tests. A key feature of the laboratory services is a hospital-wide pneumatic transportation or tube system (the Sample Subway). The pneumatic tube system is a transport system where the passengers are medicines, samples and blood bags. Many tracks, numerous trains and many more stations are how the system runs at Kokilaben Hospital. There are stations at all ward courtyards, operating rooms, ICUs and in the outpatient clinics. Using this system, the laboratory can accept more samples safely and securely.