Mechanical ball method

The manual ball method for the visual detection was already mentioned in the early fifties but it still took about 25 years until this method for the clot detection could be automated.

In the end of the seventies the company Heinrich Amelung GmbH automated this method with the semi-automatic ball coagulomter "KC10". Worldwide thousandfold employed the mechanical detection with the ball belongs to the standard methods of the coagulation analysis.

The MERLINmedical GmbH took up this method in the year 2003 and began to develop and produce a completely new generation of analysers, now based on the latest hard- and software standards.

Measuring principle

A measuring cuvette with a stainless steel ball inside slowly turns around its longituninal axis. As the measuring block is sloping slightly, the ball ball always remains at the deepest point of the cuvette due to gravity and a defined magnetic field. On this level is a magnetic sensor which responds to a dislocation of the ball.

The clotting reaction is initiated through the test-dependant added reagent. The clotting thread which is formed pulls the ball out of the detection range of the magnetic sensor and stopps the before started electronic time measurement.

The in our coagulometer, which are called MC (MERLIN Coagulometer) in the following, employed ball method is a semi-automatic mechanical clotting end point method. This is used for the determination of prothrombin times (PT), activated partial thromboplastin times (APTT), fibrinogen concentrations as well as for other clottingtests. With the ball method all clotting time tests can be performed, which have the fibrin formation as end point. Qualitative and quantitative tests can be employed. In connection with suitable reagents plasma as well as whole blood can be used as sample.

Sample and reagents are added manually into the cuvette in the MC. The time keeping till the clotting end point is effected automatically. If the parameters have been presetted correctly then e.g. ratio, %, seconds, mg, INR and LYSE-time are calculated electively by means of the prothrombin times.