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 healt h care workers that will increase with the increasing availability of point-of-care testing using capillary blood obtained with a lancet. Ob jectives. - To demonstrate the safety and efficacy of a portable pulse d erbium : yttrium-aluminum-garnet (Er: YAC) laser in obtaining a bloo d sample from patients in a clinical setting and to determine whether the laser radiant energy alters the level of various components of blo od, resulting in misleading laboratory results. Design. - Comparison o f laboratory values of blood samples obtained with the laser and conve ntional lancet and comparison of patient and user preferences by quest ionnaire. Patients and Methods. - One hundred patients with diabetes m ellitus attending a diabetes clinic were randomized to have capillary blood sampling from the fingertip performed either by the laser or a c onventional lancet first, then with the other device. Main Outcome Mea sures. - A comparison of pain, healing, hematocrit, and glycosylated h emoglobin (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 perfor ation, resulting in higher operator preference. Although patients felt greater pain and experienced slower healing with the laser, these wer e 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 un suitable 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 routi ne tests without a needle. This needle-free method will decrease the r isk of bloodborne infections caused by needlestick injuries and thus l ead to considerable cost savings and public health advantages. Further work is needed to alter the laser energy so that hemolysis can be dec reased, thus enabling a more reliable potassium estimation.