A portable device for detecting and quantifying a concentration of a marker, for example TROPONIN I, present in a sample of biological fluid, said device comprising: - a cartridge adapted to receive said biological fluid sample and comprising at least one reactive agent configured to bind to the marker defining an electrochemiluminescent solution; said cartridge comprising an electrode cell configured to supply electrical energy to the electrochemiluminescent solution so as to trigger an electrochemiluminescence reaction of said electrochemiluminescent solution, generating a light signal representative of a concentration value of said marker in said biological fluid sample; - an analyzer, connected or connectable to said cartridge and configured to receive said light signal and analyze at least one property of said light signal so as to quantify a concentration of said marker in the biological fluid; wherein said cartridge comprises: - a chamber for receiving said biological fluid sample, preferably with a conical or frustoconical shape, adapted to collect said biological fluid sample; - a first reaction chamber, arranged in fluid communication with said receiving chamber and comprising a first reactive agent configured to bind to said marker of said biological fluid sample; - a second reaction chamber, arranged in fluid communication with said first reaction chamber, said reaction chamber being interposed between the receiving chamber and the second reaction chamber, and comprising a second reactive agent configured to bind to said marker of said biological fluid sample; said second reaction chamber comprising a covering element transparent to the electromagnetic radiation generated by said electrochemiluminescence reaction to allow the reception of the electromagnetic radiation by the analyzer; characterized in that said cartridge comprises a washing chamber, arranged in fluid communication with said second reaction chamber and comprising an absorption element configured to absorb and remove from said second reaction chamber an excess portion of said electrochemiluminescent solution; said excess portion of said electrochemiluminescent solution being a portion of said excess biological fluid sample and/or a portion of said first reactive agent not bound to said marker and/or a portion of said second reactive agent not bound to said marker; preferably said absorption element being made of hydrophilic material, even more preferably said absorption element being made of cellulose diacetate. - a cartridge adapted to receive said biological fluid sample and comprising at least one reactive agent configured to bind to the marker defining an electrochemiluminescent solution; said cartridge comprising an electrode cell configured to supply electrical energy to the electrochemiluminescent solution so as to trigger an electrochemiluminescence reaction of said electrochemiluminescent solution, generating a light signal representative of a concentration value of said marker in said biological fluid sample; - an analyzer, connected or connectable to said cartridge and configured to receive said light signal and analyze at least one property of said light signal so as to quantify a concentration of said marker in the biological fluid; - a chamber for receiving said biological fluid sample, preferably with a conical or frustoconical shape, adapted to collect said biological fluid sample; - a first reaction chamber, arranged in fluid communication with said receiving chamber and comprising a first reactive agent configured to bind to said marker of said biological fluid sample; - a second reaction chamber, arranged in fluid communication with said first reaction chamber, said reaction chamber being interposed between the receiving chamber and the second reaction chamber, and comprising a second reactive agent configured to bind to said marker of said biological fluid sample; said second reaction chamber comprising a covering element transparent to the electromagnetic radiation generated by said electrochemiluminescence reaction to allow the reception of the electromagnetic radiation by the analyzer;