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Clinical laboratory in a Hospital setting showing several automated analysers.

A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.[1]

Contents

Departments

Laboratory medicine is generally divided into four sections, and each of which is further divided into a number of units. These four sections are:

Genetics is also studied along with a subspecialty known as cytogenetics.

Distribution of clinical laboratories in health institutions varies greatly from one place to another. Take for example microbiology, some health facilities have a single laboratory for microbiology, while others have a separate lab for each unit, with nothing called a "microbiology" lab.

Laboratory equipment for hematology (black analyser) and urynalisis (left of the open centrifuge).

Here's a detailed breakdown of the responsibilities of each unit:

  • Microbiology receives almost any clinical specimen, including swabs, feces, urine, blood, sputum, cerebrospinal fluid, synovial fluid, as well as possible infected tissue. The work here is mainly concerned with cultures, to look for suspected pathogens which, if found, are further identified based on biochemical tests. Also, sensitivity testing is carried out to determine whether the pathogen is sensitive or resistant to a suggested medicine. Results are reported with the identified organism(s) and the type and amount of drug(s) that should be prescribed for the patient.
  • Parasitology is a microbiology unit that investigates parasites. The most frequently encountered specimen here is faeces. However, blood, urine, sputum, and other samples may also contain parasites.
  • Virology is concerned with identification of viruses in specimens such as blood, urine, and cerebrospinal fluid.
  • Hematology works with whole blood to do full blood counts, and blood films as well as many other specialised tests.
  • Coagulation requires citrated blood samples to analyze blood clotting times and coagulation factors.
  • Clinical Biochemistry usually receives serum or plasma. They test the serum for chemicals present in blood. These include a wide array of substances, such as lipids, blood sugar, enzymes, and hormones.
  • Toxicology mainly tests for pharmaceutical and recreational drugs. Urine and blood samples are submitted to this lab.
  • Immunology/Serology uses the concept of antigen-antibody interaction as a diagnostic tool. Compatibility of transplanted organs is also determined.
  • Immunohaematology, or Blood bank determines blood groups, and performs compatibility testing on blood donors and recipients. It also prepares blood components, derivatives, and products for transfusion.
  • Urinalysis tests urine for many analytes. Some health care providers have a urinalysis laboratory, while others don't. Instead, each component of the urinalysis is performed at the corresponding unit. If measuring urine chemicals is required, the specimen is processed in the clinical biochemistry lab, but if cell studies are indicated, the specimen should be submitted to the cytopathology lab, and so on.
  • Histopathology processes solid tissue removed from the body (biopsies) for evaluation at the microscopic level.
  • Cytopathology examines smears of cells from all over the body (such as from the cervix) for evidence of inflammation, cancer, and other conditions.
  • Electron microscopy prepares specimens and takes micrographs of very fine details by means of TEM and SEM.
  • Genetics mainly performs DNA analysis.
  • Cytogenetics involves using blood and other cells to get a karyotype. This can be helpful in prenatal diagnosis (e.g. Down's syndrome) as well as in cancer (some cancers have abnormal chromosomes).
  • Surgical pathology examines organs, limbs, tumors, fetuses, and other tissues biopsied in surgery such as breast mastectomys.

Medical laboratory staff

Clinical laboratory in a Hospital setting with two technicians shown.

The following is the hierarchy of the clinical laboratory staff from highest authority to lowest:

Some of these titles don't exist in some countries. Sometimes technologists and technicians do the same work. In France, clinical biologists may also be Medical director and laboratory manager.

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 a 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.

In many countries there are mainly three types of Medical Laboratories as per the types of investigations carried out. 1. Clinical Pathology 2. Clinical Microbiology & 3. Clinical Biochemistry laboratories. 1. Clinical Pathology: Haematology, Histopathology, Cytology, Routine Pathology2. Clinical Microbiology: Bacteriology, Mycobacteriology, Virology, Mycology, Parasitology, Immunology, Serology.3. Clinical Biochemistry: Biochemical analysis, Hormonal assays etc.Blood Banks:- Blood bank is a separate body. Its laboratory need Microbiological analysis for infectious diseases that may be found in blood. Pathology to observe Blood grouping, Haematology & cross matching reactions. It also involves PRO department for the communication & contact for blood donations etc..

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 scanned 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 analysers, that process a fraction of the sample and return one or more "results". Some laboratories use robotic sample handlers (Laboratory automation) to optimize the workflow and reduce contamination risk and sample handling of the staff.

The work flow in a lab is usually heavy from 2:00 am to 10:00 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 phlebotomists for results to be available in the patient's charts for the attending physicians 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. These specimens will be processed in the evening and overnight to ensure results will be available the following day.

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, validation and interpretation

According to ISO 15189 norm, all pathological results must be verified by a competent professional. In some countries staff like clinical scientists do the majority of this work inside the laboratory with abnormal results referred to the relevant pathologist. In others, only medical staff (pathologist or clinical biologist) is concerned by this phase. It can be assisted by some software in order to validate normal or non modified results. Medical staff are sometimes also required in order to explain pathology results to physicians. For a simple result given by phone or for a technical problem it's a medical technologist explaining it to a registered nurse.

Departments in some countries are exclusively directed by a specialized Pathologist, in others a consultant, medical or non-medical, may be the Head of Department. Clinical Scientists have the right to interpret and discuss pathology results in their discipline in many countries, in Europe they are qualified to at least Masters level, may have a PhD and can have an exit qualification equivalent to medical staff e.g. FRCPath in the UK. In France only medical staff (Pharm.D. and M.D. specialized in Anatomical pathology or Clinical biology) can discuss pathological results, clinical scientists are not considered as a part of medical staff.

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. Some commercial labs 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 mid 1990s with the SmithKline Beecham (now GlaxoSmithKline) Clinical Laboratory (SBCL) scandal.[2] 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 (commercial labs have nothing to do with hospitals) 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.

The accrediting body in Australia is NATA, all laboratories must be NATA accredited to receive payment from Medicare.

See also

References

  1. ^ Farr, J. Michael; Laurence Shatkin (2004). Best jobs for the 21st century. JIST Works. p. 460. ISBN 1563709619. http://books.google.es/books?id=xBRWAAAAMAAJ.  
  2. ^ LabScam retrieved on August 26, 2007

External links








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