Medical laboratory

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


A medical laboratory or clinical laboratory is a laboratory where tests are done on biological specimens in order to get information about the health of a patient.


The laboratory is often divided into a number of disciplines:

Medical laboratory staff

The following is the hierarchy of the clinical laboratory staff from highest authority to lowest: pathologist, pathologist assistant, laboratory manager, department supervisor, chief technologist (lead technologist), cytotechnologist, medical technologist, histotechnologist, medical laboratory technician, medical laboratory assistant (lab aide), phlebotomist, transcriptionist, and specimen processor (secretary).

Types of laboratory

In many countries, there are two main types of labs that process the majority of medical specimens. Hospital laboratories are attached to a hospital, and perform tests on patients. Private (or community) laboratories receive samples from general practitioners, insurance companies, and other health clinics for analysis. These can also be called reference laboratories where more unusual and obscure tests are performed.

For extremely specialised tests, samples may go to an environmental science or research laboratory.

A lot of samples are sent between different labs for uncommon tests. It is more cost effective if a particular laboratory specializes in a rare test, receiving specimens (and money) from other labs, while sending away tests it cannot do.

Specimen processing and work flow

Sample processing will usually start with a set of samples and a request form.

Typically a set of vacutainer tubes containing blood, or any other specimen will arrive to the laboratory in a small plastic bag, along with the form.

The form and the specimens are given a laboratory number. The specimens will usually all receive the same number, often as a sticker that can be placed on the tubes and form. This label has a barcode that can be wanded by automated analyzers and test requests uploaded from the LIS. Entry of requests onto a laboratory management system involves typing, or scanning (where barcodes are used) in the laboratory number, and entering the patient identification, as well as any tests requested. This allows laboratory machines, computers and staff to know what tests are pending, and also gives a place (such as a hospital department, doctor or other customer) for results to go.

For biochemistry samples, blood is usually centrifuged and serum is separated. If the serum needs to go on more than one machine, it can be divided into separate tubes.

Many specimens end up in one or more sophisticated automated analyser, that process a fraction of the sample and return one or more "results".

The work flow in a lab usually is heavy from midnite to 7:00 am. Nurses and doctors generally have their patients tested at least once a day with general complete blood counts and chemistry profiles. These orders are then drawn during a morning run by phlebtomists. This way the med techs can test the specimens and have the results in the patient's charts for the doctors to consult during their morning rounds. Another busy time for the lab is after 3:00 pm when private practice physician offices are closing. Couriers will pick up specimens that have been drawn throughout the day and deliver them to the lab. Also, couriers will stop at outpatient drawing centers and pick up specimens.

Laboratory informatics

Laboratories today are held together by a system of software programs and computers that exchange data about patients, test requests, and test results known as a Laboratory information system or LIS. The LIS is interfaced with the hospital information system.

This system enables hospitals and labs to order the correct test requests for each patient, keep track of individual patient or specimen histories, and help guarantee a better quality of results as well as printing hard copies of the results for patient charts and doctors to check.

Result analysis

The pathology results must be verified and sometimes explained to a physician by a clinical pathologist. The majority of the time it's a medical technologist explaining it to a registered nurse.

Scandal in the clinical lab industry - SmithKline Beecham

As medical technology advanced doctors were able to get more and more tests done in shorter and shorter amounts of time. Where in the past a doctor might order a potassium and glucose and it would take hours for the results, now a doctor can order a full chemistry panel of 20 or more different analytes and get the results in under an hour. The results are also much more accurate and reliable now than in the past. Thus, into the 1970s and 1980s the lab became a source of profit within the hospital structure. Many lab corporations began taking illegal and nefarious actions to increase their income. These practices included medicare and medicaid fraud by performing and billing for tests that the ordering physician never ordered, paying kickbacks to private doctor offices for sending their specimens to these reference labs, and other complicated criminal activity. These kickbacks included donuts, free computers, fax machines, and more. These events culminated mostly in the 1980s with the SmithKline Beecham (now GlaxoSmithKline) Clinical Laboratory (SBCL) scandal.[1] It is believed SBCL paid at least $325 million in penalties and the industry as a whole paid over $1 billion to insurance and government agencies that were defrauded. Ever since this time, the lab has become a source of expense and loss in the hospital budget and lab medicine's reputation was given a black eye. Now many labs have a compliance officer with mandatory annual meetings about compliance for all employees.

Medical laboratory accreditation

Credibility of medical laboratories is paramount to the health and safety of the patients relying on the testing services provided by these labs. The international standard in use today for the accreditation of medical laboratories is ISO 15189 - Medical laboratories - particular requirements for quality and competence.

Accreditation is done by the Joint Commission, AABB, and other state and federal agencies. CLIA 88 or the Clinical Laboratory Improvement Amendments also dictate testing and personnel.

See also



  1. LabScam retrieved on August 26, 2007

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