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How to select the ideal hematology analyzer.

Looking for the best instrument to suit your needs? You'll save time and money by consulting the treasury of advice offered here.

AFTER MONTHS of tedious preparation, our facility had won approval for a major capital improvement project to upgrade several expensive pieces of equipment in our laboratory. One of these upgrades involved purchasing a new hematology analyzer. As we began to pursue various options available on the market, we quickly learned that all hematology analyzers are not created equal.

This article is not intended to evaluate specific hematology analyzers or to recommend one piece of equipment over another. Rather, it is intended to provide laboratory managers with guidance on selecting an instrument that will best suit their needs.

* Assessment tool. While members of our lab management staff had always considered themselves qualified to make wise purchasing decisions, we felt that we needed a more efficient way to zero in on what individual vendors could offer our facility. We knew from the start that our search for an outstanding hematology analyzer would be a real challenge. Every vendor representative offered five-part differentials, closed vial sampling, and at least 18 parameters with histograms. They all asserted that their analyzer was the best on the market. Each claimed to have won out consistently over major competitors in side-by-side comparison tests.

To help judge the individual qualities of each instrument, we developed a comprehensive questionnaire, which we gave to any vendor vying for our business. Each salesperson was asked to complete the survey and return it to us when that manufacturer's instrument was brought into the laboratory for a trial period.

This document served several purposes. First, it helped eliminate vendors who were clearly unable to meet our needs. Second, certain responses triggered more questions to ask during the evaluation process, Finally, the survey provided important documentation to which we could refer when making our final decision. Figure 1 combines most of the questions from our original questionnaire with the later ones we asked vendors when their products were brought to us for assessment.

For the most part, we learned that vendors appreciate having an opportunity to highlight on paper the special features of their products. A few were reluctant to answer questions related to service calls, the cost of replacement parts, the number of instruments currently in service, and similar matters. Nevertheless, no one refused to comply. Any salesperson who wanted our business acceded to our requests

* Ironing out terms. After weeks of studying all the instruments we fell knowledgeable enough to prepare bid specifications for vendors who remained in the running. Among the key issues that we closely scrutinized were data management, long-term expenditures, and extended warranties--typically expensive.

Another important consideration was to obtain guaranteed prices for reagents. To calculate the reasonable yearly usage costs associated with operating each instrument, we asked every vendor to include in their bids the costs for all reagents and controls. Taking this step enabled us to obtain guaranteed reagent pricing for the next five years.

* Wise shopping. More suggestions on how to be a wise shopper follow.

Independent analysis. When possible, ask vendors to leave their analyzers in the laboratory for a few days so that your staff can assess the instrument at their convenience in the absence of an eager rep. Vendors often offered us their instruments for at least three days.

Comparison chart. Create a chart that will reflect at a glance the comparative benefits of every instrument being considered. Dissimilarities in equipment often become more apparent when they are highlighted in black and white, particularly once you have begun to establish what you want--and don't want--in a system.

Reserving first impressions. Don't let yourself strongly favor one instrument too early in the decision process. You may be amazed by the offers that come your way once you request additional incentives, especially as it gets closer to finalizing a deal or designing your bid specs around a specific instrument.

Doing all the research is worth every minute it takes. Good luck!

Tommy Lee Camden, M.S., MT(AMT) is laboratory director for the City of Lubbock (Tex.) Health Department.

Figure 1

Probing questions for vendors and evaluators

I. General information

Name of instrument


List price

Approximate bid price

Price of maintenance contract

What kinds of discounts are available on extended warranties?

Optional attachments (autoloader, data management system, T & B lymphocytes, bar code reader, ticket printer, other).

Length of time system has been in use (excluding manufacturer's trials)

Approximate number of instruments used and distributed in U.S.

Approximate number of instruments used and distributed worldwide

Earlier model or antecedent apparatus

How long has your company been manufacturing hematology equipment? Has it ever been marketed by another company or under a different name?

II. Confirmation of specs

What is the minimum space needed for your analyzer and reagents?

What services are required to maintain the vacuum, drainage, and voltage?

Is it necessary to control electrical interference?

Is it necessary to control the atmospheric environment?

What are the analyzer's effects on the environment, if any (for example, acoustical disturbance, vibration disturbance, electrical or mechanical safety)?

III. Training

Is your instruction book clearly written with adequate information for servicing and fault finding?

What special training is required for routine use of the system?

What special training is required for maintenance?

Does your company provide local training sessions or is training conducted elsewhere?

How many of our employees would be trained as primary operators according to the purchasing agreement?

Are training costs included in the purchase?

Are travel costs included in the training (for instance, gas mileage, airfare, food, lodging)?

IV. Instrumentation


What is the principle of each test performed?

Have detailed specifications of the instrument been provided?

Does the system have closed vial sampling capability?

Do the plastic shields covering the rubber stoppers on the specialized evacuated tubes pose a problem?

Describe input of samples into the system for testing.

Can program selection be modified at a user's discretion?

Can a user select CBC with differential versus CBC without differential?

How many parameters will this instrument test?

Does this system provide a three- or five-part differential?

Is the differential interpretive or directly measured?

What is the throughput time?

What is the practical number of analyses per instrument per day?

How much time is required to start your analyzer up from a complete shutdown? Do you recommend turning the instrument off at night or over the weekend when it is not being used?

How much time is required to shut down the system each day?

Does the analyzer have a reagent warning and sensory system? Does it detect when reagents run low? Will it complete an analysis before shutting down if a low reagent is detected?

Does the system automatically clean the aspirator when used for sampling in the open vial or secondary mode? Is manual wiping required?

Do carryover or mode-to-mode programs exist within the data management system to evaluate instrument performance?

Are veterinary programs available for analyzing animal specimens?

Which parameters can be calibrated by in-house staff? Which parameters require calibration by technical field personnel? What is the recommended minimum calibration frequency for this instrument?

Are there any unique safety features on this analyzer?

Provide information on your validation methodology and the procedure we must use before putting this equipment on line and verifying linearity claims.


Is your system equipped for automated sampling? If so, is this capability standard or optional? If optional, what is the cost?

If the system does not have an autoloader, can the system be upgraded to include this feature?

When using the autoloader, how long can a user be away from the instrument once it is fully loaded (this does not mean tests per hour)?

How many specimens can be loaded onto the autoloader at one time?

Do Stat specimens create any difficulties in correctly identifying or interrupting the run in progress when using the autoloader?

Bar coding

Is your system equipped with a bar code reader for specimen identification? If so, which bar codes can be used for this system? Is bar coding a standard feature?

Does the position of the bar code pose any problems on the tube? Once bar coded, does the tube have to be placed in the cassette holder in any particular position so that the bar code reader can detect and correctly identify the specimen?

Are quality control materials bar coded for easy loading of assay values and automatic assignment to correct QC file?

V. Maintenance

Describe any alarm systems in place for instrument failure or disturbance.

What is the life expectancy of the tubing, laser, circuit boards, pumps, or other major components?

What is the average cost for replacing expensive items such as the circuit boards and laser?

Approximately how many service calls have been made per year for the last three years?

What is the average mean time between service calls for the last three years?

What is the name and address of the nearest authorized service facility to this laboratory?

What is your total parts inventory for your system?

How many technicians are employed at your nearest facility?

How many field service technicians are available for on-site service?

What is the hourly rate for shop labor?

What is the hourly labor rate for field service labor?

What is the average response time that can be expected for a service call to this laboratory?

What is the average delivery time for parts not found in inventory?

About how long will replacement parts be available for your system?

Explain the standard warranty coverage of your instrument.

What is your procedure for handling defective parts or poor quality of materials or workmanship?

For how many years has this particular system been in production?

If your service facility is located outside this city, explain your process for performing warranty work, service not covered under the warranty, and service work performed once the warranty has expired.

Who is responsible for transportation expenses should the unit require service out of town during the warranty period?

What is your method for calculating the transportation expense of out-of-town service?

State (in years) the useful life and expected downtime of your instrument.

What parts of your system are considered consumables and therefore not covered under your service contract? What is the annual usage of these consumables?

VI. Specimens

What type of anticoagulant does your system require?

Does the system have microsampling capability? If so, what is the dilution factor?

Can prediluted specimens of capillary blood be used? Will the system autocalculate for the dilution factor?

Do calibrators and control products come in cap-piercing vials?

What mechanism is available on the instrument to reject unsuitable specimens (hemolyzed, clotted, low volume)?

What is the specimen volume required for closed tube, open tube, and capillary specimen analysis?

VII. Reagents

List all required reagents, their functions, and the volumes used in single analysis as well as lapped analyses.

What is the unopened shelf life of each reagent?

What is the opened shelf life of each reagent?

Are reagents only supplied by your company, or are suitable reagents available from other commercial suppliers as well? If so, will using them jeopardize the warranty or the service contract?

What volume of reagents is used for priming the instrument and per run of 2, 25, and 100 specimens?

What reference materials/calibrators are required? What do they cost?

Are other suitable reference materials available for this instrument?

Are reagents prepackaged as a unit or purchased separately?

What is the monthly cost of calibrators and controls?

Do the routine quality control materials also control the quality differential? Must additional materials or procedures be purchased or followed?

Do any reagents require neutralization before discarding? If so, explain the procedure.

Are special calibrators needed and available for calibrations as opposed to day-to-day controls?

Provide detailed costs of all reagents needed to operate your system based on blood specimens per year for our institution.

VIII. Data management


Does your analyzer have a dedicated PC or data management system? Can the data management system be upgraded, and if so, how?

How large is the DMS? Detail its specifications.

Is the system capable of multitasking duties? Can you edit data while the instrument is analyzing specimens?

Does the system have standard bidirectional computer linkup capability?

Can the internal DMS be upgraded using future software revisions?

If the system can be upgraded with an autoloader, does the software program require a change? If so, how much more is the new software?

Will the system accept both alpha and numeric data entry?

How many patients with full reportable results can be stored internally in the system? When the system is full, can the results be downloaded to floppy disks for external storage?

How much optional demographic information can be assigned to a patient? Is this possible at both pre- and post-analysis?

Can the patient report be modified to the operator's discretion? Detail the various options available for creating a typical report.

How many scatterplots and histograms can the system store?

Can the system generate a pre- and post-load list?

Are password security options available to operate the analyzer? Can they be easily printed for QA records?

If the standard system has an optional DMS attached, who is responsible for its warranty?

Does the system have flags for RBC size and color as well as WBC flags for left shift, atypical lymphs, and blasts?

Is a help screen available throughout the DMS system?

Does the DMS use an easy-to-follow window format?

Quality control

Does the system have Levey-Jennings-type QC programs?

How many points or days of data are possible for each control level?

Does the system have Westgard rules within its QC program?

Does your company have an interlaboratory QA program? Can the data be transmitted via modem to your facility for analysis?

Does the system have an "X-BAR" or moving averages program? If so, how many and which parameters does the system track?

Does the moving average program selectively remove data from the calculation with Bull's formula?

Does the system have a reproducibility program?

How many control files are available? How many lines of data can be stored in each control file?

How many lines of data can be deleted or rejected from the QC programs? Is the information totally erased or highlighted as unacceptable? Are security measures in place to prevent QC data from being erased?

When assaying controls, how are values outside the assigned ranges brought to the operator's attention? Can the system be shut down automatically if QC values are out of range?

IX. Laboratory management staff response

How friendly is the DMS to operate?

What problems emerged during the in-house evaluation?

Did the sales rep answer all our questions without hesitation and rectify any problems that occurred as we evaluated the system?

Could our lab staff perform the required maintenance and minor repairs? How much time would it take?

How easy is the system to operate compared with the other instruments under consideration?

How great is the noise level compared with that of the other instruments under consideration?

Is the flagging criteria easy to interpret?

Is the instrument easy to calibrate? Does it hold calibration values on target?

How easy is it to set up the control libraries?

During on-site evaluation, did we have to call the troubleshooting hotline? Was it helpful?

Is there good correlation between the instrument under evaluation and the one we use now?

How well does the system separate white cell subpopulations in the cytogram?

Was significant carryover noted between specimens?

How quickly can data be retrieved from previous runs?

What distinct advantages does this system have over the other analyzers we are considering?

How does this instrument rank in relation to the other instruments under evaluation?
COPYRIGHT 1993 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993 Gale, Cengage Learning. All rights reserved.

Article Details
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Author:Camden, Tommy Lee
Publication:Medical Laboratory Observer
Date:Feb 1, 1993
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Next Article:Creating a bar code chemistry system.

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