Lumenectomy material is tested to determine the presence or likelihood of a condition of a patient. The lumenectomy material is in the form of at least one continuous tissue strand collected in vivo from an inner surface of a body lumen of the patient. The presence of at least one marker of a disease is determined. The disease may be hypertension, hyperlipidemia, depression, obesity, metabolic syndrome, insulin resistance, kidney damage, or diabetes. The patient is identified as having or as likely to develop the disease if a marker of the disease is identified in the lumenectomy material of the patient.