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It's All in the Syringe

Saul N. Weingart, MD, PhD | August 1, 2006
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The Case

A 33-year-old man with type 2 diabetes presented to his physician's office to discuss his diabetes management. The patient admitted not taking his medications or checking his blood sugars regularly. In the office, his blood sugar was 335 mg/dL, so the nurse practitioner (NP) ordered 6 units of regular insulin to administer.

After the medical assistant brought the insulin and syringe, the NP prepared the medication and injected the insulin. Immediately after the injection, the NP discovered that a tuberculin syringe was used instead of an insulin one. As a result of the error, the patient inadvertently received 60 units of insulin rather than 6 units. The patient was given orange juice, a sandwich, and his blood sugars were closely monitored for 4 hours with no significant events.

The Commentary

Office-based physicians prescribe pills and potions at a dizzying rate. Altogether, clinicians wrote more than 1.6 billion prescriptions in the United States in 2004.(1) This amounts to 5.4 prescriptions for every U.S. resident.(2) Patients leave the doctor's office with a prescription in hand in 7 out of 10 visits.(1) An increasing number of prescriptions are written electronically, although the precise number is not known.(3) While doctors and nurses interview, examine, diagnose, and counsel, the prescription pad is never far away.

Although most prescription medications are dispensed by the pharmacy for patients to self-administer at home, ambulatory practices also provide and administer medications in the office. We dispense and administer antihistamines, antipyretics, and analgesics to relieve the symptoms of allergy, fever, and pain. We administer injection therapies, including vaccinations, vitamin B12, intramuscular antibiotics and analgesics, depot contraceptives and antipsychotics, and intramuscular, articular, or bursal anti-inflammatories. Some offices also administer injection medications that patients are uncomfortable administering at home, such as erythropoietin, testosterone, and interferon. Finally, we may offer urgent treatments with triptans for acute migraine, albuterol for asthma, epinephrine for anaphylaxis, nitroglycerin for chest pain, and insulin for hyperglycemia. A striking feature of this list is the variety of medications administered and the broad indications they address, with the likelihood that a given practice or provider might only care for a few patients requiring a specific drug.

Although medication administration in the office is widespread, it is potentially risky, as illustrated in the case presented. In this case, a medical assistant handed a tuberculin syringe to a NP who assumed it was an insulin syringe, accidentally administering a 10-fold insulin overdose to a patient with moderate hyperglycemia. Although the error was detected immediately and addressed appropriately, the potential for harm was real.

This case illustrates the paucity of safeguards for medication administration in the ambulatory setting. Consider first the medication use process in the inpatient setting. For medications to be administered to a hospitalized patient, the physician must order the medication in an electronic system or on a paper form. If the system is electronic, safeguards include typed orders to ensure legibility, fixed fields to enforce complete prescriptions, dose-range checks, drug allergy and drug interaction checks, and accessible drug reference materials. In paper-based systems, orders are usually transcribed and then reviewed by a nurse for accuracy and completeness before being forwarded to the pharmacy. In the pharmacy, orders are again entered and reviewed to ensure they are safe and complete before the medication is dispensed. Dispensing then requires multiple checks before the drugs are finally delivered to the unit. Pharmacists in many hospitals place medications in electronic dispensing cabinets, where nurses must enter a code to retrieve the medications. The nurse then follows a standard protocol for confirming the patient's identity and the drug name, dose, route, and time before administering the medication.

Compare this multi-step approach to the medication administration process in office practice. In the simplest case, the physician, physician assistant, or NP decides to administer a medication that is stocked onsite. He or she draws up an injection medication and administers the drug directly to the patient. That's it. In a slightly more elaborate scenario, he or she may ask another staff member to fetch the drug or to prepare and deliver the medication themselves, a dramatically abbreviated process compared to inpatient medication administration.

The simplicity of office-based medication administration avoids many hazards of inpatient care related to complexity, miscommunication, and handoffs. However, improved efficiency comes with the loss of checks and redundancies that help ensure patient safety. Unless the patient obtains a drug at the pharmacy and carries it back to the office for administration, there is no written prescription, no decision support, no second clinician double-check, no pharmacist intervention, no "smart" cabinet. Documentation may be inconsistent and difficult to find, perhaps included in an office note or listed on a flow sheet or problem list. When we administer medications in the office, we are, in effect, driving without standard safety equipment: no bumpers, no high beams, no horn, no anti-lock brakes, no airbags, no seatbelts. We can do better.

If we performed a root cause analysis of the case of the mixed-up syringe, we might ferret out latent conditions that contributed to this error. The analysis might uncover environmental factors that increased the risk of a mix-up, such as poor lighting in the "med" room. In addition, the tuberculin syringe might have been boxed next to the insulin syringe, or perhaps they were mixed together in a common bin on a crowded shelf. The analysis might also identify deficiencies in education and training. For example, the medical assistant may have been new to the job, not properly oriented or trained, and unaware of the difference between various syringe types. There were probably communication problems. The NP may not have specified that she wanted an insulin syringe. Perhaps she was unable to confer with a physician about the management of the case and the need for immediate treatment. Working conditions may have contributed as well. Heavy patient volume, urgent cases, add-on visits, and unexpected staff absences could all have increased the day's workload and production pressure. Finally, the practice probably lacked policies for the use of high-hazard drugs such as insulin, such as mandatory double-checks of drug name and dose.

Insulin holds a special place in the pantheon of high-risk medications. Insulin errors and injuries are common among hospitalized patients.(4-9) The risk of treatment-related hypoglycemia is particularly high among frail elderly patients after hospital discharge.(9)

Insulin overdoses due to confusion between insulin and tuberculin syringes are well known, at least in the hospital setting. In a case reported in a 2002 Institute for Safe Medication Practices alert, a nurse administered a 10-fold overdose to a hospitalized patient after the hospital switched its syringe vendor.(10) The new tuberculin and insulin syringes had similar packaging and were accidentally stocked in the same drawer. The "mL" markings on the syringe were mistaken for units. And, the tuberculin syringe had an orange plunger tip similar to that used for many years on insulin syringes. In 2004, the Pennsylvania Patient Safety Authority also issued a tuberculin-insulin syringe advisory following three 10-fold insulin overdoses attributed to packaging and syringe design.(11)

Informed by the inpatient experience, professional organizations have advanced a variety of recommendations for improving insulin safety in the hospital.(5-8) For example, the work environment should be organized into bins and buckets that are clearly labeled and appropriately stocked. Staff members should be oriented and trained. Organizations should create policies and procedures that specify double-checks for insulin (or other high-risk medications) and "read-back" confirmation of verbal orders. Special care should be exercised and training instituted with packaging and labeling changes and when items are obtained from new vendors.

Most of these recommendations are also appropriate for ambulatory care and are consistent with our root cause analysis. The challenge, of course, is redesigning systems for solo or small group practices that ensure safety while maintaining efficiency. In addition to striking such balances, office-based practitioners should consider the opportunity to partner with patients and their families.(12) In the case of the mixed-up syringe, could the patient have prevented the incident? It is likely that the patient had more experience administering insulin than his or her caregivers. Had the patient been invited to review the drug and dose or to administer the medication, the error might have been averted. Clinicians certainly cannot abdicate responsibility for patient safety.(13) Nevertheless, patients and their families may offer an untapped source of resilience, a resource for enhancing safety in ambulatory care.

Take-Home Points

  • Clinicians administer a wide range of medications in ambulatory care.
  • Few of the medication safeguards required or available in hospitals are used routinely in office-based practice.
  • Office-based clinicians should implement medication safety measures, particularly for high-risk drugs such as insulin. These safe practices should ensure that medications and related supplies are clearly labeled and stocked, that staff members receive appropriate training, and that clinicians double check the drug name, dose, and patient identification prior to administration.
  • Office-based clinicians should also seek opportunities for patient participation in medication safety.

Saul N. Weingart, MD, PhD Vice President for Patient Safety and Director of the Center for Patient Safety, Dana-Farber Cancer Institute Assistant Professor of Medicine, Harvard Medical School


1. Hing E, Cherry DK, Woodwell DA. National Ambulatory Medical Care Survey: 2004 Summary. Advance Data from Vital and Health Statistics, No. 374. Hyattsville, MD: National Center for Health Statistics; June 23, 2006. Available at: Accessed July 5, 2006.

2. Table 2. Population: 1960-2004. In: Population. Statistical Abstract of the United States: 2006. Washington, DC: US Census Bureau; 2006. Available at: Accessed July 31, 2006.

3. A call to action: eliminate handwritten prescriptions within 3 years! Huntingdon Valley, PA: Institute for Safe Medication Practices; 2000. Available at: Accessed July 31, 2006.

4. Bates DW, Cullen DJ, Laird N, et al. Incidence of adverse drug events and potential adverse drug events: implications for prevention. JAMA. 1995;274:29-34. [go to PubMed]

5. Insulin errors: a common problem. USP Patient Safety CAPSLink. July 2003. Available at: Accessed July 5, 2006.

6. Hellman R. A systems approach to reducing errors in insulin therapy in the inpatient setting. Endocr Pract. 2004;10(suppl 2):100-108. [go to PubMed]

7. Bates DW. Unexpected hypoglycemia in a critically ill patient. Ann Intern Med. 2002;137:110-116. [go to PubMed]

8. Bates D, Clark NG, Cook RI, et al. American College of Endocrinology and American Association of Clinical Endocrinologists position statement on patient safety and medical system errors in diabetes and endocrinology. Endocr Pract. 2005;11:197-202. [go to PubMed]

9. Shorr RI, Ray WA, Daugherty JR, Griffin MR. Incidence and risk factors for serious hypoglycemia in older persons using insulin or sulfonylureas. Arch Intern Med. 1997;157;1681-1686. [go to PubMed]

10. Safety brief. ISMP Medication Safety Alert! Acute Care Edition. November 13, 2002. Available at: Accessed July 31, 2006.

11. Supplementary Advisory: Overdoses caused by confusion between insulin and tuberculin syringes. PA-PSRS Patient Safety Advisory. October 24, 2004. Available at: pa-psrs_supplementary_advisory_v1_s1.pdf. Accessed July 31, 2006.

12. Reduce adverse drug events involving insulin: permit patients to self-administer insulin. Institute for Healthcare Improvement. Available at: IndividualChanges/Permit+Patients+to+Self-Administer+Insulin.htm. Accessed July 31, 2006.

13. Entwistle VA, Mello MM, Brennan TA. Advising patients about patient safety: current initiatives risk shifting responsibility. Jt Comm J Qual Patient Saf. 2005;31:483-494. [go to PubMed]

This project was funded under contract number 75Q80119C00004 from the Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services. The authors are solely responsible for this report’s contents, findings, and conclusions, which do not necessarily represent the views of AHRQ. Readers should not interpret any statement in this report as an official position of AHRQ or of the U.S. Department of Health and Human Services. None of the authors has any affiliation or financial involvement that conflicts with the material presented in this report. View AHRQ Disclaimers
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