Accuracy & Precision in Clinical Chemistry Analyzers: Role of Probes

Accuracy & Precision – Part 1 – Role of number of probes in fully auto clinical chemistry analyzer

If we talk about fully automatic clinical chemistry analyzers, few of them are having single (common) probe for sample & reagent transfer, while few analyzers are having separate probes for sample & reagent transfer.

Generally, it is believed that separate probes (one) for sample and (second) for reagent transfer are required to reduce carry-over &/or cross-over but reality is different.

Let’s take an example of fully auto clinical chemistry analyzer having two separate probes for sample and reagent transfer, in this analyzer, reagent probe will transfer all reagents i.e. Glucose, Urea, SGPT, Creatinine. . . So, chances of carry-over &/or cross-over are always there between two reagents. Same way sample probe will transfer all samples i.e. sample number 01 (HIV positive), sample number 02 (normal sample), sample number 03 (HCV positive). . . So, chances of carry-over &/or cross-over are always there between different samples.

Actually, it’s not number of probes (separate for reagent & sample) but “Advanced Washing Protocol” & “Type of Probe / Mixer”, which ensures reduction in carry-over & cross over. More number of probes are required to increase the speed (throughput) of analyzers.

Beacon group of companies are offering full range of clinical chemistry analyzers having throughput of 100, 200, 400 and 800 tests / hour. Low throughput analyzers (100 & 200 tests / hour) are equipped with single probe. Medium throughput analyzer (400 tests / hour) is equipped with two probes (separate for sample & reagent). High throughput analyzer (800 tests / hour) is equipped with three probes (one probe for sample & two probes for reagents) as well as two mixers.