Within the sub-acute care population studied, 32% of all patients had pending lab tests, and the vast majority of these were omitted from hospital discharge summaries. Microbiology cultures were the most common type of lab pending at the time of hospital discharge, and many of these did not have preliminary results available by the day of patient discharge. The majority (82%) of these pending cultures without preliminarily available results were urine cultures.
Similar to previous studies of general medical populations2,3
, our study provides evidence that pending lab tests in sub-acute care populations are common at the time of discharge, but are frequently omitted in written discharge communications. The sub-acute care population, in particular, is high risk. Complicated transitions (i.e., a visit to the emergency department or a re-admission to the hospital within 30 days of discharge) occur frequently in this population7
. Furthermore, these patients are often unable to advocate for themselves (as co-morbid dementia is common)19,20
, and are heavily reliant on good discharge summary communication for a smooth transition to a sub-acute care facility6,7
. If key information regarding pending lab tests is left out of the discharge summary, important follow-up of critical lab results may not occur, possibly leading to medical errors and patient harm, with increased risk of re-admission.
This study is the first to look closely at preliminarily available microbiology results. Preliminary culture results are available to clinicians in the LIS, and clinical decisions may be made based upon preliminary results. However, even taking this into consideration, discharge summary omissions of pending microbiology tests remain high. After excluding cultures for which preliminary results were available, 24-hour urine culture results were not available for 82% of patients with pending urine cultures and 48-hour blood culture results were not available for 19% of patients with pending blood cultures at the time of hospital discharge.
Hip fracture patients are at increased risk of re-hospitalization within 30 days for complications such as wound infection, septicemia, and pneumonia21
. Among acute stroke patients discharged to sub-acute care, 20% either return to the emergency department or are re-hospitalized during the first 30 days following discharge, and 19-25% of these returns are due to infections such as aspiration pneumonia and urosepsis7
. The high prevalence of poorly communicated pending labs for vulnerable sub-acute care patients found in this study, especially urine and blood cultures, raises significant patient safety concerns given the present poor state of discharge communication5
. Further study is needed to determine the impact that such pending lab omissions have on post-hospital patient outcomes. Of specific interest is whether the omission of pending culture results is associated with post-discharge infectious complications and re-hospitalizations.
Our approach has some limitations. We used a very conservative definition for “pending” (lab tests which returned on or after the first post-discharge day), and there were likely instances where laboratory test results came back later in the same day that a patient was discharged. Our approach would not have labeled these tests as pending and may have resulted in underestimation of the problem of pending labs at discharge.
We did not assess whether the results of the pending lab tests were actionable, i.e., would have changed patient management, as some others have done2,3
. However, our unique focus on preliminarily available microbiology results strengthens the argument that pending labs are clinically significant. We recognize that preliminarily available microbiology results can be incomplete, yet we included them because preliminary lab results are widely utilized to inform clinical decision-making22–24
In our study, we did not specifically assess whether physicians were aware of the pending lab test. We also did not assess whether a separate communication (such as a phone call or fax) relayed the pending lab test to the sub-acute care facility. However, previous studies have shown that physicians are often displeased with their lab test results management system25
, and that separate physician-to-facility communication rarely occurs26–28
. As such, we suspect that only a small proportion, if any, of the pending labs were communicated outside the standard discharge summary channels.
The use of data from a single, large, academic teaching hospital may limit the generalizability of these results. In contrast to smaller hospitals, clinical laboratories at large, academic teaching hospitals have sophisticated lab testing capabilities and infrequently need to send out tests for processing. The number and category of lab tests pending at the time of discharge, and pending lab test omissions from the discharge summary may be different at smaller hospitals due to the differences in clinical laboratory size and testing availability. Therefore, our study of an academic center may underestimate the prevalence of pending labs at smaller hospital facilities with fewer resources.
Many opportunities exist to improve the communication of pending lab tests to the next setting of care. For example, automated laboratory systems such as the LIS may become an important tool for improving communication of pending lab tests at hospital discharge because it captures lab tests that are truly “collected and pending.” This makes it ideal for automating their inclusion in the discharge summary, the only mandated communication directed to the next provider of care5
. Another opportunity pertains to the designation of the party responsible for the follow-up of pending labs. Hospital policies generally do not explicitly state who is responsible for following up on a pending lab test—the ordering hospital-based provider or the provider caring for the patient post-discharge29
. Most often, these are two different people6
. A formal designation of this responsibility may be important to ensure prompt attention to lab results which return after the patient’s discharge and to maximize timely and appropriate post-hospital patient care.
Findings from this study and others could be used to design targeted interventions to improve the communication of pending lab tests at discharge. Identifying patients with complex medical problems being discharged to sub-acute care facilities could subsequently trigger a more comprehensive discharge and care transition procedure. This might involve a dedicated professional (such as a geriatric nurse practitioner) managing the discharge process and personally communicating key information, including pending lab tests, to the next setting of care.
In conclusion, this study’s findings highlight an important shortcoming in discharge summary communication which may adversely affect sub-acute patient care. Future studies should focus on improving the communication of pending lab tests at discharge, and evaluating the impact that this improved communication has on patient outcomes.