A patient of approximatel...

A patient of approximately 30 years of age, with no prior medical history or complaints, volunteered for blood donation. During the donation process, incidentally found  that the patient had thick blood that clots easily, which raised concerns about underlying health issues. Seeking clarification, the individual approached a medical laboratory for further investigation. Once again, during the sampling procedure, the thick consistency of the blood made it difficult to draw. Despite these findings, the laboratory tests, including BT, CT, and PT, all the results within normal limits. Kindly suggest thge further line of investigation?