How many venipuncture attempts are permitted on a single patient? Is there a rule that limits the number of attempts that can and should be made?

The real issue in venipuncture is not “how many attempts” but “when to stop.” Knowing when to stop or defer a venipuncture requires assessing the patient and the clinical situation, and evaluating whether the initial attempt has already produced a complication. The purpose of policies to limit multiple attempts at drawing blood is not to set a fixed number of attempts but to preclude multiple attempts when it would potentially be injurious to the patient.

From a risk-management standpoint, guidance for phlebotomists should reflect the reasonable legal and clinical concerns, and clearly establish and appropriately enforce the policy. Because of the potential for complications, an assessment of the possible adverse outcomes is needed in drafting a useful and reasonable policy.

Minor complications of venipuncture are local and relatively common — up to 15% in some studies, most of which consider minor complications as bruising, hematoma, or transient pain. Such problems are more common in women, most notably bruising, which occurs about five times as often in women as it does in men. Minor complications, by definition, resolve completely and without medical intervention, though they may be temporarily bothersome. Serious complications can be local or systemic, are much less common — generally less than 3% overall — and include diaphoresis, syncope, seizure, and temporary arrhythmias. Patient injury from these reactions generally occurs secondarily, for example, when syncope induces a fall that results in a scalp laceration.

Nerve injury can occur as a result of direct trauma or because of compression as a result of hematoma. To determine the rate of such injuries is difficult, but they, too, are relatively uncommon. Injuries of this type can result in permanent damage and have even been associated with the development of reflex sympathetic dystrophy, a painful and often progressive condition that affects skin, nerves, muscles, and even bones and joints.

The first avoidance of a repeat attempt is when the patient objects; refusal is an absolute contraindication to an additional attempt until and unless permission is given again. Proceeding in the face of a patient’s objection could raise issues of battery, as could proceeding in the face of a serious request to stop once the attempt is underway. The use of topical anesthetics can reduce the incidental pain from phlebotomy, resulting in more relaxed and cooperative patients (especially children) and fewer objections.

When patients show evidence of direct nerve trauma (shock-like pains, burning pain, pins and needles, especially when it involves the distal arm and fingertips), the attempt should be stopped immediately; there should not be a second attempt in the same site. Similarly, if the first attempt has resulted in significant local bleeding which could result in nerve compression, the procedure should be halted. In either case, further attempts to draw blood should be deferred until the patient is evaluated for the complication that has already occurred, if for no other reason than to get baseline documentation of his status.

Recognition of patient conditions and clinical circumstances that increase the risk of complication is also a basis for restricting the number of attempts. Patients with bleeding disorders or those on anticoagulants present an increased risk for localized bleeding. Although additional attempts may be warranted, care should be exercised not to exhaust available sites; appropriate post-phlebotomy care should be instituted to limit bruising in sites where multiple attempts were made.

Any hard-and-fast rule about the number of permitted attempts is likely to be arbitrary; not more than two venipuncture attempts is the most common standard. In general, most patients do not require a second attempt. The average number of attempts in one study of 500 samples drawn reported 1.25 attempts per successful draw. A second attempt — if necessary, at a second site — in the absence of potential complicating factors is generally medically reasonable. Keep in mind that any such limit is a maximum; depending on the patient and other circumstances, it may be both reasonable and prudent not to make more than one attempt. If a patient is agreeable to two or more attempts, documenting informed consent is wise.

More important than a specific number of permitted attempts are good training, oversight, and reporting to help phlebotomists perform within their skills and their patients’ needs. Making sure an experienced phlebotomist is always available to assist or relieve a less-experienced colleague will help ensure that second attempts are productive. Tracking complications can identify phlebotomists whose higher-than-average complication rates may indicate a need for additional training. A post-phlebotomy questionnaire also can provide helpful information by assessing patient satisfaction in situations where no complication is reported but some less-than-optimal result occurs.

Barbara Harty-Golder is a pathologist-attorney consultant in Chattanooga, TN. She maintains a law practice with a special interest in medical law. She writes and lectures extensively on healthcare law, risk management, and human resource management.