P RINCIPLES OF C LINICAL C HEMISTRY A UTOMATION

A UTOMATION I N C LINICAL C HEMISTRY The modern clinical chemistry laboratory uses a high degree of automation. Many steps in the analytic process that were previously performed manually can now be performed automatically. This Permits the operator to focus on tasks that cannot be readily automated and increasing both efficiency and capacity.

A UTOMATION I N C LINICAL C HEMISTRY The analytic process can be divided into three major phases— preanalytic, analytic, and postanalytic—corresponding to sample processing, chemical analysis, and data management, respectively. Substantial improvements have occurred in all three areas during the past decade. The analytic phase is the most automated, and more research and development efforts are focusing on increasing automation of the preanalytic and postanalytic processes.

W HY A UTOMATION ? Increase the number of tests by one person in a given period of time Minimize the variations in results from one person to another Minimize errors found in manual analyses – equipment variations – pipettes Use less sample and reagent for each test

T YPES O F A NALYZERS Continuous Flow Tubing flow of reagents and patients samples Centrifugal Analyzers Centrifuge force to mix sample and reagents Discrete Separate testing cuvets for each test and sample Random and/or irregular access

C ONTINUOUS F LOW This first “AutoAnalyzer” (AA) was a continuous-flow, single-channel, sequential batch analyzer capable of providing a single test result on approximately 40 samples per hour. Analyzers with multiple channels (for different tests), working synchronously to produce 6 or 12 test results simultaneously at the rate of 360 or 720 tests per hour.

In continuous flow analyzers, samples were aspirated into tubing to introduce samples into a sample holder, bring in reagent, create a chemical reaction, and then pump the chromagen solution into a flow-through cuvette for spectrophotometric analysis. C ONTINUOUS F LOW

The major drawbacks that contributed to the eventual demise of traditional continuous-flow analyzers in the marketplace were significant carry-over problems and wasteful use of continuously flowing reagents.

C ONTINUOUS F LOW Continuous flow is also used in some spectrophotometric instruments in which the chemical reaction occurs in one reaction channel and then is rinsed out and reused for the next sample, which may be an entirely different chemical reaction.

C ENTRIFUGAL A NALYZERS Discrete aliquots of specimens and reagents are piptted into discrete chambers in a rotor The specimens are subsequently analyzed in parallel by spinning the rotor and using the resultant centrifugal force to simultaneously transfer and mix aliquots of specimens and reagents into radially located cuvets. The rotary motion is then used to move the cuvets through the optical path of an optical system

D ISCRETE ANALYZERS Discrete analysis is the separation of each sample and accompanying reagents in a separate container. Discrete analyzers have the capability of running multiple tests on one sample at a time or multiple samples one test at a time. They are the most popular and versatile analyzers and have almost completely replaced continuous-flow and centrifugal analyzers.

D ISCRETE A NALYZERS Sample reactions are kept discrete through the use of separate reaction cuvettes, cells, slides, or wells that are disposed of following chemical analysis. This keeps sample and reaction carryover to a minimum but increases the cost per test due to disposable products.

H ITACHI 902 A NALYZER

W ITH AUTOMATION THERE IS STILL SOME VERY BASIC STEPS Specimen preparation and Identification Labeling still critical Programming of instrument Laboratory personnel must perform and observe: Quality Assurance Quality Control

TOTAL LABORATORY AUTOMATION

S ELECTION P ROCESS What is your lab’s workload like? Discrete or large batch testing? Single instrument or multiples? Storage of reagents Need refrigeration or freezing? expense Kept at room temperature until reconstituted

P OINT OF CARE TESTING

D EFINITION Point-of-care testing (POCT) has been defined by the College of American Pathologists (CAP) as “those analytical patient-testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories.”

P LACE OF ANALYSIS Physician’s offices Operating rooms Emergency rooms Intensive Care Units Home health care Patient performed

P ERSONNEL I SSUES Most often performed by non-laboratorians Physicians Nurses or nurses aides Respiratory technicians Not specifically trained in the requirements for accurate testing and interpretation

L ABORATORY S UPPORT Laboratory still responsible for results Therefore responsible for training and management of POCT programs Laboratory must build a structure to support and facilitate POCT

S UPPORT S TAFF Director - PhD, MD or laboratory scientist or pathologist POC Coordinator – laboratory scientist with high level technical & interpersonal skills POC Trainers – designated person(s) for problem solving etc.

C OMMON A PPLICATIONS Glucose Testing Chemistries Electrolytes Blood gases Hematology Coagulation – ACT Hematocrit