Semi-Automatic Coagulation Analyzer with Optical Clot Detection

What is the Semi-Automatic Coagulation Analyzer with Optical Clot Detection?

This analyzer detects clot formation optically by measuring the change in light scatter as fibrin forms in the cuvette. It is the most common semi-automatic design and suits clinics and laboratories that need reliable prothrombin time and APTT results in small batches.

Overview

A light source and photodetector are positioned across a temperature-controlled cuvette, and the instrument records transmitted or scattered light continuously after reagent addition. As fibrin strands form, scatter increases and the instrument marks the clotting point when the signal change exceeds a defined threshold, usually with a selectable sensitivity. Two or four measuring channels run in parallel, and incubation positions pre-warm plasma and reagent to 37 degrees Celsius. The analyzer stores calibration curves for each reagent lot and calculates the prothrombin time ratio and international normalised ratio from the international sensitivity index. Because detection depends on an optical signal, samples that are icteric, hemolyzed or lipemic should be flagged, and the instrument prompt for such samples is a useful quality feature.

How does it work?

A semi-automatic coagulation analyzer provides a temperature-controlled measuring position, usually at 37 degrees Celsius, a detection system and a timer. The operator pipettes plasma into the cuvette, incubates it, adds the reagent and starts the measurement. Optical instruments detect the increase in turbidity or the change in light scatter as fibrin strands form; mechanical instruments detect the change in movement or viscosity of a steel ball or magnetic particle; turbidimetric and chromogenic instruments measure light absorption changes from the fibrin network or from a coloured product released by a synthetic substrate. The analyzer stops the timer at the detection threshold and reports the clotting time in seconds, a ratio for prothrombin time or a concentration for fibrinogen. Because sample and reagent handling remain manual, pipetting accuracy and consistent incubation timing have a large influence on results.

What are the key features?

• Continuous optical monitoring of light scatter in the cuvette
• Two or four parallel measuring channels
• Selectable detection threshold sensitivity
• Prewarming positions at 37 °C for plasma and reagent
• Prothrombin time ratio and INR calculation from the ISI
• Audible timer and prompt for turbid or coloured samples

What are the technical specifications?

A typical semi-automatic coagulation analyzer with optical clot detection configuration offers detection principle of Optical scatter change, 660 nm LED, channels of 2 or 4 parallel measurement channels, incubation temperature of 37 °C ±0.3 °C, sample volume of 50–100 µL plasma per test, reagent volume of 50–100 µL per test and measuring range of PT 5–100 s; APTT 15–150 s. 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 Semi-Automatic Coagulation Analyzer with Optical Clot Detection is used in routine PT and APTT testing in clinics, INR monitoring in anticoagulation clinics, pre-operative coagulation screening and thrombin time and fibrinogen measurement. Across the wider Semi-Automatic Coagulation Analyzers class, laboratories also deploy it for routine PT and APTT testing in clinics, anticoagulation monitoring with INR and pre-operative coagulation screening.

Which standards and certifications apply?

Relevant standards and methods include ISO 15189, CLSI H57, CLSI H21, CLSI EP05, ICSH recommendations on coagulation 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.

Place the analyzer on a level bench away from vibration and draughts, since both disturb optical clot detection, and allow the instrument to reach and hold 37 degrees Celsius before use. Verify performance at installation against a reference instrument or assigned plasma samples for prothrombin time, APTT and fibrinogen, and check the incubation temperature with an external thermometer. Daily work includes running normal and abnormal control plasma, checking reagent and cuvette lot numbers and recording all values. Reagents must be reconstituted, stored and expired strictly according to the instructions, and citrated plasma should be separated, frozen and thawed under controlled conditions because pre-analytical handling has a large influence on clotting times.

How do I select the right Semi-Automatic Coagulation Analyzer with Optical Clot Detection?

Specify this variant when plasma samples are typically clear and the menu is limited to clotting time assays. In the RFQ confirm the number of channels, the incubation temperature specification, whether the international sensitivity index can be entered per reagent lot, and how the instrument handles samples that are visibly lipemic or icteric.

How does it compare with other Semi-Automatic Coagulation Analyzers variants?

Choose the detection principle according to the samples you receive: mechanical or magnetic detection tolerates icteric, hemolyzed and lipemic plasma, while optical detection is simpler and usually requires a clear sample. Then decide how many channels you need, because a four-channel instrument allows several patients or duplicate measurements in one run and reduces operator waiting time. Check the menu the instrument supports, especially whether fibrinogen, D-dimer or antithrombin assays are available, since not every semi-automatic platform can perform chromogenic or immunoturbidimetric tests. Confirm the sample and reagent volumes, the incubation temperature accuracy and the calibration requirements, and ask whether the analyzer stores calibrator values for each reagent lot.