Chemistry Instrumentation Solo 1 Lecture 1 Study Guide

3 benefits of clinical chemistry automation

Assists technologists in test performance - Automation has the ability to process large workloads without comparable increases in staff

Assesses results of the tests performed - The most significant improvement in the quality of lab test results due to automation is the reduction in variability of results

It reduces or eliminates monotonous and repetitive tasks - Processing transporting and loading specimens

Sequential Analysis

Each specimen enters the analytical process one after the other. Each result or set of results emerges in the same order as the specimens are entered

Batch Analysis

Many specimens are grouped (batched) in the same analytical session. Only one analyte is ran at a time. Different assays may be ran on an analyzer by switching the reagents

Single Channel Analysis

Each specimen is subjected to a single process so that only results for a single analyte are produced. Example: Osmo

Multiple Channel Analysis

Each specimen is subjected to multiple analytical processes so that a set of test results is obtained on a single specimen. Example: Complete Metabolic Panel, Basic Metabolic Panel

Parallel Analysis

All specimens are subjected to a series of analytical processes at the same time and in a parallel fashion, Centrifugal analyzers use discrete pipetting to load aliquots of specimen and reagents sequentially into discrete chambers. The specimens are subsequently analyzed in parallel. Analyzers are set up to be either a multiple-specimen/single-chemistry mode (running the same test on several specimens in parallel) or single-specimen/multiple chemistry mode (running multiple tests in parallel on one specimen)

Random Access Analysis

Most common configuration of analyzers, any specimen, by a command to the processing system in analyzed by any available process in or out of sequence with other specimens. Each specimen may be analyzed for a different selection of tests for each specimen may be requested by either the operator or downloads from a LIS

8 Individual steps required to complete a chemistry analysis, known as unit operations

Sample Identification: The analyzer will scan/read the barcode on the labeled primary specimen tube or aliquot tube. This information can also be entered manually

Determine Tests to Perform: Upon barcode scanning, test order information is retrieved from the LIS and automatically sent over to the analyzer via interface

Reagent Systems and Delivery: One or more reagents can be dispensed into the reaction cuvette

Specimen Measurement and Delivery: A small aliquot of the patient sample is introduced into the reaction cuvette

Chemical Reaction Phase: The patient sample and reagents are mixed and incubated

Measurement Phase: Optical readings may be initiated before or after all reagents have been added

Signal Processing and Data Handling: The analyte concentration (result) is estimated from a calibration curve that is stored in the analyzer

Send Results to Middleware/LIS: The analyzer sends results for the ordered tests via an interface to the middleware/LIS and subsequently to the electronic medical record

Benefit of using a liquid level sensor during sample loading and aspiration

Minimization of splatter

3 ways to reduce carryover of analyte or reagent from one specimen reaction to another

Disposable sample probe tips

Flushing of the internal and external surfaces of the sample probe

Setting an appropriate flush-to-specimen ratio and incorporating wash stations for the sample probe. Ratio may be as much as 4:1 to limit carryover. Using certain material sand controlling dispenser velocity allow for lower wash ratio

Information included on a reagent label

Reagent identification, volume or number of tests to be used, expiration date and lot number

Information that must be written on the reagent pack after opening

Initials, Date, and Time

3 factors of the chemical reaction phase that must be controlled

The vessel in which the reaction occurs (reaction vessel)

The cuvette in which the reaction is monitored

The timing of the reaction

Mixing and transport of reactants

Thermal conditioning of fluids

Autoverification

Automatically releasing results that have no associated problems

Bidirectional Interface

The analyzer can receive data from the patient’s sample barcode and also transmit results to the LIS in electronic formats

Recommended sequence of events for the operator to follow

Preventative Maintenance

Reagent Loading

Calibration

Quality Control

Operating Instrument

Evaluating Diagnostic Messages