Keating K, Rohloff M, Cicic A et al: Are postoperative laboratory studies following robotic assisted radical prostatectomy necessary? Urol Pract 2021; 8: 510.

In the past, standard postoperative orders following open prostatectomies at our institution included obtaining routine laboratory studies such as a complete blood count (CBC) and basic metabolic panel (BMP). While robotic assisted radical prostatectomy (RARP) has provided many benefits, including lower levels of blood loss and transfusion rates compared to open prostatectomy, our institution continued obtaining routine laboratory panels every postoperative day in our robotic cohort.¹ In our quest to improve value-based care by eliminating unnecessary testing, we sought to determine if routine postoperative laboratory studies were necessary and attempted to calculate any potential cost savings by omitting these studies.

We performed a retrospective review of 200 patients who had undergone RARP over an 18-month period with a focus on evaluating for laboratory abnormalities along with any required intervention secondary to those abnormalities (eg administration of electrolytes, blood products or consultation to other services).² Two robotic surgeons with varying levels of experience were included in this study. Inclusion criteria consisted of RARP patients greater than 45 years old with biopsy proven prostate cancer. Subjects without postoperative laboratory studies were excluded. The cohort did not include patients with salvage prostatectomies, and a majority of RARPs were performed with pelvic lymph node dissection and nerve sparing. Laboratory costs were tabulated based on Medicare reimbursement at our facility, which was $10.58 for a CBC and $11.52 for a BMP.²

Of the 200 patient records reviewed, only 15 patients had a laboratory abnormality of hypokalemia (average potassium level of 3.3 mmol/l) requiring replacement. No additional laboratory abnormalities were noted, and no patient in this cohort required a blood transfusion. Our cohort’s comorbidities included hypertension (52%), coronary artery disease (24.5%), diabetes mellitus (18.5%), and renal insufficiency (6%). Preoperative comorbidities were not associated with an increased risk of laboratory abnormalities. Patient age, body mass index, estimated blood loss, operative time, or Gleason score did not demonstrate significance in laboratory abnormalities. Most patients’ pathology was T2c (54%) with a Gleason score of 7 (66.3%). The overall cost of these laboratory studies for this cohort was $4,232 for a CBC and $4,608 for a BMP with an average length of stay of 2 days.

The utility of routine postoperative studies after RARP is low based on the results of our cohort. Only 15 of 200 patients required medical intervention for hypokalemia, and no patients required a blood transfusion for postoperative anemia. Mild hypokalemia, as demonstrated in our cohort, has minimal clinical significance in the literature, and most patients are asymptomatic at levels of 3.0–3.5 mmol/l.³ In addition to a paucity of intervention based on laboratory studies, annual cost savings of omitting these laboratory studies, when applied at our institution, would be approximately $6,000 per year. While $6,000 per year is a low institutional cost savings, extrapolating these savings to RARPs performed throughout the U.S. would amount to savings of approximately $1.6 million annually per postoperative day if other institutions collected a CBC and BMP (approximately 72,000 RARPs are performed per year).^4,5

Laboratory values such as CBC and BMP have minimal cost and can provide a surgeon with valuable information; however, as surgeons, we should continually reevaluate our practices as technology evolves. Thus, we made an institutional change to omit postoperative labs after RARP. The necessity of postoperative labs is evaluated in our patients with intraoperative variables such as estimated blood loss and postoperative variables such as vital signs, Jackson-Pratt output, urine output, and physical examination. As hospitals and payers move more toward value-based care, eliminating low yield studies will be a high priority.