Quantitative HCG testing methods?

[melraek23]

What are other facilities using for quantitative hcg testing? We are currently using the miniVidas but may be moving all other testing to a different analyzer. I am not sure what options there are out there and just looking for some input to aime me in the right direction. Thanks!

[Auntie-D]

We use Seimens Centaur CP and it's dreadful. Expensive technology, lots of dead space in the sampling (makes for lots of QC wastage), takes ages to initialise and you cannot do a dilute sample straight off (you have to do a neat and a dilute) which means that lots of reagent is wasted. The NEQAS isn't too hot either. Oh and did I mention the down time and the fact that it is super noisy? Don't go Seimens!!!!

[SMILLER]

We have been using a Beckman-Coulter Access for some time. No particular problems that I know of. Cals are once/month. We also use it for BNPs and some other non-STAT tests. Maintenance is minor and little downtime for repairs.

[Bill]

I have use Abbott Axsym and Abbott Ci8200 with no particular problems. Run from 0-5000 in about 15-17 minutes and can program for autodilution above that in another 15-17 minutes. Cal curves are approx 3 months. Sample volume about 100 ul.

[Jillybean]

I'm sorry to barge in on this thread. I don't know anything about lab equipment, but I have a question for all of you. I had been going to one lab to get a stat quantitative hcg test and it was always reported as an exact number. However, I went to a different lab and they reported it as "greater than 5,000." Have you ever heard of that? Does that mean they just stopped running it after 5,000? My nurse is perplexed, but said they may not have diluted it down properly. It just about gave me a heart attack. It seems like you lab insiders may be able to solve my mystery.

Thank you ahead of time.

[Deny Morlino]

I will take a stab at an explanation. Laboratory analyzers have a range of measurement within which the results are considered accurate and repeatable. This is checked at intervals using quality control with a "known" result and comparing the result reported from the analyzer with the "known" value. Once a result moves outside of the analyzer's range of measurement (linearity is the term used in the laboratory), the accuracy of the result is not guaranteed. When a result is determined to be beyond an instrument's linearity the result is often reported as either > a given value (in your experience >5000) or > a value. Most instrumentation is designed to dilute the sample automatically to extend the reportable range to a degree. If the result is still beyond this extended range, manual dilution prior to placing the sample on the analyzer is often possible. Any time a dilution is performed there is some degree of inaccuracy (usually very small) added to the result. It sounds like this is what you are experiencing. If your physician wants a more numeric result, they will need to discuss what is possible with the performing laboratory. Hope this helps a bit.