Lumi-Aggregometer

What is the Lumi-Aggregometer?

A lumi-aggregometer measures platelet aggregation and ATP release simultaneously, using a luciferin-luciferase reagent to detect the ATP secreted from dense granules. It suits investigation of storage pool defects and of secretion disorders.

Overview

The instrument combines an aggregometer channel with a luminescence detector. Adenosine triphosphate released from dense granules during activation reacts with luciferin and luciferase, emitting light proportional to the ATP concentration, while aggregation is measured in the same cuvette by light transmission or impedance. Comparing the two traces separates defects of aggregation from defects of secretion: a normal aggregation response with low ATP release suggests a storage pool or secretion defect, while both reduced indicates a broader platelet dysfunction. Full dose-response curves with several agonists improve diagnostic yield, and the method is usually combined with electron microscopy or flow cytometry for confirmation. Reagents must be prepared fresh, because luciferase activity declines, and the luminescence channel requires calibration before use.

How does it work?

Platelet function testing uses two main approaches. In aggregation methods, platelet-rich plasma or whole blood is stirred at 37 degrees Celsius with an agonist such as adenosine diphosphate, collagen, arachidonic acid or ristocetin. In light transmission aggregometry the sample clarifies as platelets clump and the increase in transmitted light is recorded as an aggregation curve. In impedance aggregometry platelets adhere to electrode wires and the rise in electrical impedance between them is recorded. In luminescence aggregometry, ATP released from dense granules reacts with luciferin-luciferase reagent and the emitted light is measured alongside the aggregation trace. In high-shear systems, blood is aspirated through a capillary coated with collagen and adenosine diphosphate or epinephrine, and the time until the aperture occludes is reported as the closure time. All methods depend on controlled temperature, agonist quality and prompt processing of citrated samples.

What are the key features?

• Simultaneous aggregation and ATP release measurement
• Luciferin-luciferase luminescence detection channel
• Separation of aggregation defects from secretion defects
• Dose-response protocols with several agonists
• Luminescence channel calibration before each run
• Curve storage for comparative review

What are the technical specifications?

A typical lumi-aggregometer configuration offers channels of 1–4 aggregation channels with luminescence, aggregation measurement of Light transmission or impedance selectable, luminescence detection of Photomultiplier with 0–10 nmol ATP range, ATP reference of ATP standard included for calibration, temperature of 37 °C ±0.2 °C and stir speed of 600–1200 rpm. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Lumi-Aggregometer is used in dense granule storage pool defect diagnosis, hermansky-Pudlak and related syndrome investigation, platelet secretion disorder testing and research on platelet granule release. Across the wider Platelet Analyzers class, laboratories also deploy it for investigation of inherited platelet disorders, testing for aspirin and P2Y12 inhibitor response and diagnosis of von Willebrand disease with ristocetin.

Which standards and certifications apply?

Relevant standards and methods include ISO 15189, CLSI H58, CLSI EP05, ICSH recommendations on platelet function testing, IEC 61010-1 and IEC 61010-2-101. Certification candidates for this model are CE, ISO 13485 manufacturing and NMPA class II registration; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Collect blood into citrate or hirudin as specified, avoid traumatic venepuncture and process samples within one to four hours, because platelet reactivity declines with time. Keep the aggregometer at 37 degrees Celsius, verify the temperature with an external thermometer and ensure the stir bar rotates at the specified speed. Reagents must be reconstituted and stored exactly as instructed, since degraded agonists give falsely low aggregation. Verify performance with normal control samples and review curves for shape and amplitude, not only the maximum value. Low platelet counts, hemolysis, lipemia and certain drugs affect results, so medication history should be documented before testing.

How do I select the right Lumi-Aggregometer?

Specify a lumi-aggregometer when secretion defects are part of the differential diagnosis, or when the laboratory wants both aggregation and release data from one sample. In the RFQ confirm the ATP measuring range, whether calibration standards are supplied, and the stability and shelf life of the luminescence reagents.

How does it compare with other Platelet Analyzers variants?

Choose the method according to the clinical question. Light transmission aggregometry is the classical approach and allows a full agonist panel, while impedance aggregometry accepts whole blood and is less affected by low platelet counts and lipemia. Luminescence aggregometry adds dense granule storage pool assessment. High-shear closure time systems are simple to operate and useful for screening and for monitoring antiplatelet therapy, but they give limited mechanistic information. Consider sample volume, which matters for pediatric patients, the number of channels available per run, and the reagent or agonist supply. Confirm whether your laboratory can maintain proficiency in interpretation, because aggregation curves require experience, and take part in external quality assessment where a scheme exists.