An Erbium:YAG laser to obtain capillary blood samples without a needle for point-of-care laboratory testing

Background. - Needlestick injury poses an occupational hazard to health care workers that will increase with the increasing availability of point-of-care testing using capillary blood obtained with a lancet. Objectives. - To demonstrate the safety and efficacy of a portable pulsed erbium : yttrium-aluminum-garnet (Er: YAC) laser in obtaining a blood sample from patients in a clinical setting and to determine whether the laser radiant energy alters the level of various components of blood, resulting in misleading laboratory results. Design. - Comparison of laboratory values of blood samples obtained with the laser and conventional lancet and comparison of patient and user preferences by questionnaire. Patients and Methods. - One hundred patients with diabetes mellitus attending a diabetes clinic were randomized to have capillary blood sampling from the fingertip performed either by the laser or a conventional lancet first, then with the other device. Main Outcome Measures. - A comparison of pain, healing, hematocrit, and glycosylated hemoglobin (HbAlc), blood urea nitrogen, sodium, potassium, bicarbonate, and glucose levels. Results. - Adequate blood was obtained with both devices 97% of the time. Blood flow was greater with the laser perforation, resulting in higher operator preference. Although patients felt greater pain and experienced slower healing with the laser, these were not serious problems. Modification of the laser energy output led to a reduction in pain. Possibly owing to hemolysis,the potassium level in the blood obtained with the laser was significantly elevated and unsuitable for clinical decision making in many cases. None of the other measurements were similarly affected. Conclusions. - We conclude that the laser device has the potential to obtain a blood sample for routine tests without a needle. This needle-free method will decrease the risk of bloodborne infections caused by needlestick injuries and thus lead to considerable cost savings and public health advantages. Further work is needed to alter the laser energy so that hemolysis can be decreased, thus enabling a more reliable potassium estimation.