The £90million facility will deal with more than two million tests on NHS patients a year.
Health Minister Alex Neil, who unveiled the facility, said it would help save more lives in Glasgow.
He added: "The technology we have here will be saving lives that five, 10 or 15 years ago would not have been saved.
"As patients, we don't fully appreciate the array of talent, intelligence and skill that we have behind the scenes as part of our treatment and we can take that for granted.
"This new facility shows exactly why we should be proud of the NHS, especially the NHS north of the border."
One of the most modern facilities in the UK, the laboratory has brought together 17 NHS Greater Glasgow and Clyde labs and one mortuary.
Offering services 24 hours a day and seven days a week, the building houses a genetics laboratory, which is developing tests to allow treatments tailored to patients' DNA.
There is also a blood sciences department, which performs an array of analytical tests on blood samples and a range of tests to aid diagnosis of medical conditions.
NHS bosses said that by bringing lab services into one place, samples can be processed quicker, giving patients faster results.
Mr Neil was given a tour of the facility, the first section of the £842m New South Glasgow Hospitals Campus site to be open and fully operational.
Andrew Robertson, chairman of NHS Greater Glasgow and Clyde, said: "The opening of this state-of-the-art laboratory represents the first phase of an integr-ated children's and adult hospital with maternity services on site providing the gold standard for health care.
"The new laboratory building is the first stage of a building programme that will transform the Southern General campus into a world class facility.
"It has been delivered on time and within budget and has created a multi-disciplinary approach to laboratory medicine which will benefit patients now and in the future."
The facility has more than 750 staff including medical, clinical scientists, biomedical scientists, technical assistants, administrative and clerical staff.
The laboratory's equipment deals with diagnostics for biochemistry, haematology, microbiology, genetics and pathology.
Rachel Green, associate medical director for diag-nostics, added: "The magnitude of the operation at this fine building is immense and should not be underestimated.
"More than 750 people have relocated to this new laboratory and tens of thousands of results are being generated every day to support faster turnaround times, improving our diagnostic capacity.
"With state-of-the-art equipment and fit for purpose laboratory space I am immens-ely proud to be part of the first tangible demonstration of the way that laboratory medicine is being modernised across Greater Glasgow and Clyde." Biomedical scientist Paula Elder is the team leader for the Pathology Lab and gave Mr Neil a tour of her laboratory.
Her team processes more than 1500 tissue samples a day from hospitals across the NHSGGC area.
Paula said: "This lab is far larger than the ones we are used to working in. It's the largest in Scotland and the equipment is state-of-the-art.
We are able to process samples quickly, giving patients much faster results."
Mr Neil also toured the haematology lab and met with David Cunningham, another biomedical scientist. His lab deals with liver and kidney function samples and patients' cholesterol levels.
After touring the facility, the health minister unveiled a plaque to mark the occasion.
He added: "As well as patient care this lab is seeing medical research that is putting Scotland on the world map. I believe the research done here will attract attention internationally and bring many visits by scientists from other parts of the world.
"The facilities here are brilliant. I have been very impressed by what I've seen."
THE new lab is one part of the £842million publicly funded project that will see a new children's and adult hospital built on the site of the current Southern General.
The adult hospital will have 1109 beds alongside a 256-bed children's hospital, providing maternity, paediatric and acute services.
The Southern Glasgow Hospital Campus is part of more than £2billion being invested in improving NHS facilities over the next three years.
The new South Glasgow Hospital will have 30 operating theatres and a floor area of 166,000sq m – the size of 24 football pitches.Every patient in general wards will have a single room with en-suite toilet.
The hospital's earliest buildings were in Eglinton Street before, in 1872, a 240-bed hospital and 180 patient lunatic asylum were built at the present site.