Clinical pathology

Clinical pathologyis amedical specialtythat is concerned with the diagnosis of disease based on thelaboratoryanalysis ofbodily fluids,such asblood,urine,and tissue homogenates or extracts using the tools ofchemistry,microbiology,hematology,molecular pathology,andImmunohaematology.This specialty requires amedical residency.

Hematology:Bloodsmears on a glass slide, stained and ready to be examined under the microscope.

Bacteriology:Agarplate with bacterial colonies.

Bacteriology:microscopic image of a mixture of two types ofbacteriastained with theGram stain.

Clinical chemistry:an automated blood chemistry analyser.

Clinical pathology is a term used in the US, UK, Ireland,many Commonwealth countries,Portugal, Brazil, Italy, Japan, and Peru; countries using the equivalent in the home language of "laboratory medicine" include Austria, Germany, Romania, Poland and otherEastern Europeancountries; other terms are "clinical analysis" (Spain) and "clinical/medical biology (France, Belgium, Netherlands, North and West Africa).

Licensing and subspecialities

TheAmerican Board of Pathologycertifies clinical pathologists, and recognizes the following secondary specialties of clinical pathology:

• Chemical pathology,also calledclinical chemistry
• Hematopathology
• Blood banking-Transfusion medicine
• Clinical microbiology
• Cytogenetics
• Molecular genetics pathology.

In some countries other sub specialities fall under certifiedClinical Biologistsresponsibility:

• Reproductive biologyincludingAssisted reproductive technology,Sperm bankandSemen analysis
• Immunopathology

Organization

Clinical pathologists are often medical doctors. In some countries inSouth-America,Europe,AfricaorAsia,this specialty can be practiced by non-physicians, such as Ph.D. or Pharm.D. after a variable number of years ofresidency.

In United States of America

Clinical pathologists work in close collaboration with clinical scientists (clinical biochemists, clinical microbiologists, etc.),medical technologists,hospital administrators, and referring physicians to ensure the accuracy and optimal utilization of laboratory testing.

Clinical pathology is one of the two major divisions ofpathology,the other beinganatomical pathology.Often,pathologistspractice both anatomical and clinical pathology, a combination sometimes known asgeneral pathology.Similar specialties exist inveterinary pathology.

Clinical pathology is itself divided into subspecialties, the main ones beingclinical chemistry,clinical hematology/blood banking,hematopathologyandclinical microbiologyand emerging subspecialties such asmolecular diagnosticsandproteomics.Many areas of clinical pathology overlap with anatomic pathology. Both can serve as medical directors of CLIA certified laboratories. Under the CLIA law, only the USDepartment of Health and Human Servicesapproved Board CertifiedPh.D.,DSc,orMDandDOcan perform the duties of a Medical or Clinical Laboratory Director. This overlap includes immunoassays, flow cytometry, microbiology and cytogenetics and any assay done on tissue. Overlap between anatomic and clinical pathology is expanding to molecular diagnostics and proteomics as we move towards making the best use of new technologies for personalized medicine.

Clinical pathologists may assist physicians in interpreting complex tests such asplateletaggregometry,hemoglobinor serum proteinelectrophoresis,orcoagulationprofiles. If interfering substances are suspected, they may recommend alternate test methods. For example,hemolysis,icterus,lipemia,or heterophile antibodies may confound results obtained by traditional methods such as ion-selective electrodes, enzymatic assays orimmunoassays.Alternate methods such as blood gas analysers,point-of-care testingormass spectrometrymay help resolve the clinical question.

In Europe

Recently,EFLMhas chosen the name of "Specialists in Laboratory Medicine" to define all European Clinical pathologists, regardless of their training (M.D., Ph.D. or Pharm.D.).

In France, Clinical Pathology is called Medical Biology ( "Biologie médicale" ) and is practiced by both M.D.s and Pharm.D.s. The residency lasts four years. Specialists in this discipline are called "Biologiste médical" which literally translates asClinical Biologistrather than "Clinicalpathologist".

Tools

Microscopes, analyzers, strips, centrifuges

Macroscopic examination

Visual examination of the specimen may provide information to the pathologist or the physician. For example, fluid drained from anabscessmay appear cloudy, orcerebrospinal fluidobtained bylumbar puncturemay exhibitxanthochromia,suggesting a bleed has occurred. Laboratory technologists may provide qualitative descriptions accordingly.

Microscopical examination

See also:staining

Microscopic analysis is an important activity of the pathologist and the laboratory technologist. They have many different stains at their disposal (GRAM,MGG,Grocott,Ziehl–Neelsen,etc.). Immunofluorescence, cytochemistry, the immunocytochemistry, andFISHare also used in order make a correct diagnosis.

Pathologists may review samples such aspleural,peritoneal,synovial, or pericardial fluids to characterize them as "normal", tumoral, inflammatory, or even infectious. Microscopic examination can also determine the causal infectious agent – often a bacterium, mould, yeast, parasite, or (rarely) virus.

Laboratory Analysers

Automated analysers,by the association of robotics and spectrophotometry, have allowed these last decades better reproducibility of the results, in particular in medical biochemistry and hematology.

Efficiency and productivity can be enhanced by automating the pre-analytical processing, including barcode reading, sorting, centrifuging, and aliquoting specimens.

The analysers must undergo daily controls prior to performing patient testing. Analysers must also undergo daily, weekly and monthly maintenance. Quality management involves reviewing quality control trends to detect emerging problems in instrument calibration, correlating results between instruments that perform similar testing, and running standardized samples to prove linearity and precision.

Some laboratory processes involve automated analysis combined with manual review by technologists. For example, when hematology analysers flag samples as abnormal, automatedwhite blood celldifferential counts may be superseded by manual differential counts using stained slides read at the microscope or scanned by digital imaging software. Laboratory technologists may flag abnormal samples for pathologist review. The pathologist may recommend additional testing, such asflow cytometryto identifylymphomaorleukemiacells, orcytologyto characterize solid tumor cells.

Cultures

Samples undergoing examination for pathogens, primarily inmedical microbiology,may be incubated with culture media. Those allow, for example, the description of one or several infectious agents responsible of the clinical signs.

Values known as "normal" or reference values

Detailed article:Reference range.

See also

• Pathology
• Medical laboratory
• Anatomic pathology
• Medical technologist
• Veterinary pathology
• Clinical Biologist

External links

• American Association for Clinical Chemistry
• American Society for Clinical Pathology
• American Board of Pathology
• College of American Pathologists
• European Federation of Clinical Chemistry and Laboratory Medicine
• Academy of Clinical Laboratory Physicians and Scientists