Evaluating the Effect of Decreasing Preoperative Hemoglobin on Blood Transfusions, Major Complications, and Periprosthetic Joint Infection After Primary Total Knee Arthroplasty.

INTRODUCTION: Preoperative anemia is associated with increased postoperative transfusion and complication rates after total knee arthroplasty (TKA). We aimed to create TKA-specific data-driven preoperative hemoglobin strata that quantify the likelihood of 90-day postoperative blood transfusion and evaluate whether these strata are associated with increased risk of 90-day major complications and 2-year prosthetic joint infection (PJI). METHODS: Primary TKA patients from 2013 to 2022 were identified using a national database. Stratum-specific likelihood ratio (SSLR) analysis defined hemoglobin strata associated with the risk of 90-day blood transfusion. Each stratum was propensity score matched to the highest identified hemoglobin strata. Unmatched incidence rates and matched risk of 90-day major complications and 2-year PJI between strata were compared. RESULTS: SSLR identified four 90-day blood transfusion hemoglobin strata for men (strata [g/dL], likelihood ratio [<11.4, 8.06; 11.5 to 11.9, 4.34; 12.0 to 12.9, 1.70; 13.0 to 17.0, 0.54]) and women (<10.4, 8.22; 10.5 to 11.4, 2.84; 11.5 to 12.4, 1.38; 12.5 to 17.0, 0.50). Increased 2-year PJI risk was associated with three male strata (<11.4, 11.5 to 11.9, 12.0 to 12.9; all P < 0.001) and three female strata (<10.4, 10.5 to 11.4, 11.5 to 12.4; all P < 0.001). Increased 90-day major complication risk was associated with three male strata (<11.4, 11.5 to 11.9, 12.0 to 12.9; all P < 0.001) and three female strata (<10.4, 10.5 to 11.4, 11.5 to 12.4; all P < 0.001). CONCLUSIONS: Using SSLR analysis, we identified unique TKA-specific data-driven hemoglobin strata for both men and women that quantify the likelihood of 90-day blood transfusions and predict the risk of both 90-day major complications and 2-year PJI. These strata are a first in the TKA literature and can assist surgeons in stratifying patients' transfusion and complication risk based on their preoperative hemoglobin value. While optimizing patients in the preoperative setting, we recommend using these TKA-specific hemoglobin thresholds to help guide decision making on the need for presurgery anemia optimization and to help reduce the need for blood transfusion.

Evaluating The Effect of Arthroscopic Rotator Cuff Repair with Concomitant Subacromial Decompression on 2, 4, and 6 Year Reoperation Rates.

INTRODUCTION: The risks and benefits of including an arthroscopic subacromial decompression (ASD) during arthroscopic rotator cuff repair (RCR) are uncertain. Some studies suggest no difference in revision surgery rates, whereas others have found higher revision surgery rates associated with concomitant ASD. In this study, we compare mid-term revision surgery rates in patients undergoing arthroscopic RCR with or without concomitant ASD. METHODS: A retrospective cohort analysis was conducted using a national all-payer claims database. Current Procedural Terminology and International Classification of Disease, 10th Revision, codes were used to identify patients who underwent primary arthroscopic RCR with or without ASD in the United States. The primary study outcome was revision surgery at 2, 4, and 6 years. Univariate analysis was conducted on demographic variables (age, sex) and comorbidities in the Elixhauser Comorbidity Index using chi-square and Student t-tests. Multivariate analysis was conducted using logistic regression. RESULTS: A total of 11,188 patients were identified who underwent RCR and met the inclusion criteria. Of those, 8,994 (80%) underwent concomitant ASD. Concomitant ASD was associated with lower odds of all-cause revision surgery to the ipsilateral shoulder at 2 years (odds ratio [OR], 0.61; 95% confidence interval [CI], 0.51 to 0.73), 4 years (OR, 0.60; 95% CI, 0.51 to 0.70), and 6 years (OR, 0.59; 95% CI, 0.51 to 0.69). Concomitant ASD was also associated with lower odds of revision RCR at 2 years (OR, 0.68; 95% CI, 0.53 to 0.86), 4 years (OR, 0.63; 95% CI, 0.50 to 0.78), and 6 years (OR, 0.61; 95% CI, 0.49 to 0.76). DISCUSSION: Arthroscopic RCR with concomitant ASD is associated with lower odds of all-cause revision surgery in the ipsilateral shoulder at 2, 4, and 6 years. The lower mid-term revision surgery rates suggest benefits to performing concomitant ASD with primary arthroscopic RCR. Continued research on the mid to long-term benefits of ASD is needed to determine which patient populations benefit most from this procedure. DATA AVAILABILITY: The data that support the findings of this study are available from the corresponding author upon reasonable request.

How low can we go? A randomized controlled trial of low-quantity initial opioid prescriptions for shoulder surgery.

BACKGROUND: Orthopedic surgeons are the third most frequent prescribers of opioid medications. Given the current opioid addiction crisis, it is critical to limit opioid prescriptions to the lowest effective dose. In this study, we investigated how the initial opioid prescription after shoulder surgery affects maximum possible opioid consumption. We hypothesized that fewer pills in the initial opioid prescription would lead to less opioid consumption, a lower refill request rate, and fewer post-surgery office contacts for pain. METHODS: In this single-center, prospective, randomized controlled clinical trial, 74 adults who underwent shoulder arthroplasty, rotator cuff repair, or other arthroscopic shoulder procedures were enrolled from December 2020 to July 2022. Follow-up was completed by February 2023. Participants were randomly assigned to receive postoperative prescriptions of seven 5-mg oxycodone pills (n = 20), 15 pills (n = 29), or 23 pills (n = 25). The primary outcome was maximum possible opioid consumption within 2 weeks after surgery, calculated by assuming consumption of all pills in the initial prescription, as well as any refills. Secondary outcomes were the opioid prescription refill request rates, post-surgery pain-related telephone calls or messages to the provider's office ("office contacts") within 2 weeks after surgery, and American Shoulder and Elbow Surgeons pain scores 2 weeks after surgery. Baseline characteristics did not differ among groups except for mean age, which was younger in the 7-pill group (P = .047). RESULTS: Maximum possible opioid consumption increased with the number of pills initially prescribed, with means of 78 morphine milligram equivalents (MME) for the 7-pill group, 118 MME for the 15-pill group, and 199 MME for the 23-pill group (P < .001). None of the secondary outcome measures differed among groups. Refill request rates were 20% for the 7-pill group, 3.4% for the 15-pill group, and 12% for the 23-pill group (P = .20). The proportions of patients with at least 1 office contact were 35% in the 7-pill group, 45% in the 15-pill group, and 28% in the 23-pill group (P = .43). Mean American Shoulder and Elbow Surgeons pain scores were 49 in the 7-pill group, 44 in the 15-pill group, and 40 in the 23-pill group (P = .20). CONCLUSION: After shoulder surgery, an initial prescription of fewer opioid pills was associated with less maximum possible opioid consumption without an increase in the percentage of patients requesting opioid refills or contacting the provider's office for pain-related concerns. An initial postoperative prescription of fewer 5-mg oxycodone pills may be equally or more effective compared with larger quantities for most patients.

Higher return to sport and lower revision rates when performing arthroscopic Bankart repair with remplissage for anterior shoulder instability with a Hill-Sachs lesion: a meta-analysis.

BACKGROUND: Recurrent anterior shoulder instability remains the most common complication from a prior shoulder dislocation, especially among young and active individuals who engage in athletic activities. This instability can lead to repeated subluxation or dislocations of the humeral head from the glenoid fossa. The purpose of this study is to compare postoperative recurrence rates, instability-related revision and return to sport (RTS) rates between isolated arthroscopic Bankart repair (ABR) and ABR with remplissage (ABR + R) for anterior shoulder instability with subcritical glenoid bone loss (GBL) and a Hill-Sachs lesion (HSL). METHODS: PubMed, Embase, and Web of Science were searched on June 2022. Studies sought were those comparing postoperative outcomes of ABR + R versus isolated ABR for subcritical GBL and an HSL. Study quality was evaluated using the revised Cochrane tool. Redislocations, instability-related revisions, and RTS rates were extracted and pooled estimates were calculated using the random-effect model. RESULTS: Twelve studies were included with a mean follow-up of 48.2 months for isolated ABR and 43.2 months for ABR + R. The meta-analytic comparison demonstrated that ABR + R resulted in statistically significant improvement in Rowe and American Shoulder and Elbow Surgeons scores by 6.5 and 2.2 points, respectively; however, the improvements in patient-reported outcomes were not clinically meaningful. ABR + R resulted in reduced external rotation at the side by 1° which was not clinically meaningful and there was no significant difference in terms of forward elevation. ABR + R resulted in a statistically significant reduction of overall postoperative recurrences (odds ratio [OR]: 9.36), postoperative dislocations (OR: 6.28), instability-related revision (OR: 3.46), and RTS to any level (OR: 2.85). CONCLUSION: The addition of remplissage to ABR for recurrent anterior shoulder instability with subcritical GBL and HSL results in significantly lower postoperative instability recurrence, lower instability-related revisions, and higher RTS to any level.

The Effect of Concomitant Biceps Tenodesis on Revision Surgery Rates After Primary Rotator Cuff Repair.

INTRODUCTION: We aimed to use a national database to compare the 4-year revision surgery rates after rotator cuff repair (RCR) in patients with concomitant biceps tenodesis (BT) versus those without BT. METHODS: A retrospective cohort analysis was conducted using the PearlDiver database from 2015 to 2017. Patients undergoing primary open and arthroscopic RCR with and without BT were identified. Demographic variables, 90-day complications, and 2- and 4-year revision surgery rates were analyzed, and a multivariable logistic regression was conducted. RESULTS: Of the 131,155 patients undergoing RCR, 24,487 (18.7%) underwent concomitant BT and 106,668 (81.3%) did not. After controlling for comorbidities and demographics, patients with concomitant BT were associated with lower odds of all-cause revision (OR; P-value [0.77; P < 0.001]), revision BT (0.65; P < 0.001), revision RCR (0.72; P < 0.001), and shoulder arthroplasty (0.81; P = 0.001) within 4 years when compared with those without concomitant BT. DISCUSSION: In our analysis, patients undergoing primary RCR with concomitant BT had 35% reduced odds of revision BT and 23% reduced odds of any all-cause revision within 4 years when compared with those without concomitant BT. This suggests that tenodesis at the time of primary RCR may be associated with a reduction in the utilization of ipsilateral shoulder revision surgery rates.

Social determinants of health disparities impact postoperative complications in patients undergoing total shoulder arthroplasty.

BACKGROUND: Understanding the role of social determinants of health disparities (SDHDs) in surgical outcomes can better prepare providers to improve postoperative care. In this study, we use International Classification of Diseases (ICD) codes to identify SDHDs and investigate the risk of postoperative complication rates among patients undergoing total shoulder arthroplasty (TSA). METHODS: A retrospective cohort analysis was conducted using a national insurance claims database. Using ICD and Current Procedural Terminology (CPT) codes, patients who underwent primary TSA with at least 2 years of follow-up in the database were identified. Patients with a history of SDHDs were identified using appropriate ICD-9 and ICD-10 codes. Patients were grouped in one of 2 cohorts: (1) patients with no history of SDHDs (control) and (2) patients with a history of SDHDs (SDHD group) prior to TSA. The SDHD and control groups were matched 1:1 for comorbidities and demographics prior to conducting multivariable analysis for 90-day medical complications and 2-year surgical complications. RESULTS: After matching, there were 8023 patients in the SDHD group and 8023 patients in the control group. The SDHD group had significantly higher odds for 90-day medical complications including heart failure, cerebrovascular accident, renal failure, deep vein thrombosis, pneumonia, sepsis, and urinary tract infection. Additionally, the SDHD group had significantly higher odds for revision surgery within 2 years following TSA. Patients in the SDHD group also had a significantly longer length of hospital stay following TSA. DISCUSSION: This study highlights the association between SDHDs and postoperative complications following TSA. Quantifying the risk of complications and differences in length of stay for TSA patients with a history of SDHDs is important in determining value-based payment models and risk stratifying to optimize patient care.

The Persistent Backlog of Knee and Shoulder Orthopedic Sport Surgery Case Volume Following the COVID-19 Pandemic.

Objectives: As COVID-19 will not be the last pandemic, understanding our historical response allows us to predict and improve our current practices in preparation for the next pandemic. Following the removal of the elective surgery suspension at the onset of the COVID-19 pandemic, it is unclear whether sports medicine surgery volume has returned to pre-pandemic levels as well as whether the backlog from the original suspension was addressed. The purpose of this study to observe the monthly changes in volume and backlog of knee and shoulder sports surgery one year since the original suspension. Methods: National all-payer data was utilized to identify patients undergoing knee and shoulder sports procedures from January 2017 to April 2021. Descriptive analysis was utilized to report the monthly changes in surgeries. A linear forecast analysis using historical data was utilized to determine the expected volume. This was compared to the observed case volume. The difference in expected and observed volume was utilized to calculate the estimated change in backlog. Results: From March to May 2020, there was a persistent decrease in the observed shoulder and knee sports volume when compared to the expected volume. By June 2020, all knee and shoulder sports volume reached the expected volume. By April 2021, the estimated backlog for shoulder and knee procedures had increased by 49.8% (26,412 total cases) and 19.0% (26,412 total cases), respectively, with respect to the original calculated backlog from March to May 2020. Conclusion: Within four months, the sudden decrease in volume for knee and shoulder sports procedures had returned to pre-pandemic levels; however, the original backlog in cases has continually increased one year following the suspension. Additionally, the backlog is significantly higher for knee when compared to shoulder surgeries.

Data-driven body mass index threshold associated with increased risk of 2-year periprosthetic joint infection following total shoulder arthroplasty.

BACKGROUND: Body mass index (BMI) is a modifiable risk factor for medical and infectious complications following total shoulder arthroplasty (TSA). Previous studies investigating BMI were limited to the conventional classification system, which may be outdated for modern day patients. Therefore, the purpose of this study was to identify BMI thresholds that are associated with varying risk of 90-day medical complications and 2-year prosthetic joint infection (PJI) following TSA. METHODS: A national database was utilized to identify 10,901 patients who underwent primary elective TSA from 2013 to 2022. Patients were only included if they had a BMI value recorded within 1 month prior to TSA. Separate stratum-specific likelihood ratio analyses, an adaptive technique to identify data-driven thresholds, were performed to determine data-driven BMI strata associated with varying risk of 90-day medical complications and 2-year PJI. The incidence rates of these complications were recorded for each stratum. To control for confounders, each BMI strata was propensity-score matched based on age, sex, hypertension, heart failure, chronic obstructive pulmonary disease, and diabetes mellitus to the lowest identified BMI strata for both outcomes of interest. The risk ratio (RR) and 95% confidence interval (CI) were recorded for each matched analysis. RESULTS: The average age and BMI of patients was 70.5 years (standard deviation ±9.8) and 30.7 (standard deviation ±6.2), respectively. Stratum-specific likelihood ratio analysis identified two BMI strata associated with differences in the rate of 2-year PJI: 19-39 and 40+. The same strata were identified for 90-day major complications. When compared to the matched BMI 19-39 cohort, the risk of 2-year PJI was higher in the BMI 40+ cohort (RR: 2.7; 95% CI 1.39-5.29; P = .020). After matching, there was no significant difference in the risk of 90-day major complications between identified strata (RR: 1.19, 95% CI: 0.86-1.64; P = .288). CONCLUSION: A data-driven BMI threshold of 40 was associated with a significantly increased risk of 2-year PJI following TSA. This is the first TSA study to observe BMI on a continuum and observe at what point BMI is associated with increased risk of 2-year PJI following TSA. Our identified BMI strata can be incorporated into risk-stratifying models for predicting both PJI and 90-day major complications to minimize both.

Social Determinants of Health Disparities Increase the Rate of Complications After Total Knee Arthroplasty.

BACKGROUND: Few studies have investigated whether social determinants of health disparities (SDHD), which include economic, social, education, health care, and environmental factors, identified through International Classification of Diseases (ICD) codes are associated with increased odds for poor health outcomes. We aimed to investigate the association between SDHD, identified through this novel methodology, as well as postoperative complications following total knee arthroplasty (TKA). METHODS: Using a national insurance claims database, a retrospective cohort analysis was performed. Patients were selected using Current Procedural Terminology and ICD codes for primary TKA between 2010 and 2019. Patients were stratified into 2 groups using ICD codes, those who had SDHD and those who did not, and propensity matched 1:1 for age, sex, a comorbidity score, and other comorbidities. After matching, 207,844 patients were included, with 103,922 patients in each cohort. Odds ratios (ORs) for 90-day medical and 2-year surgical complications were obtained using multivariable logistical regressions. RESULTS: In patients who have SDHD, multivariable analysis demonstrated higher odds of readmission (OR): 1.12; P = .013) and major and minor medical complications (OR: 2.09; P < .001) within 90-days as well as higher odds of revision surgery (OR: 1.77; P < .001) and periprosthetic joint infection (OR: 1.30; P < .001) within 2-years. CONCLUSION: The SDHD are an independent risk factor for revision surgery and periprosthetic joint infection after TKA. In addition, SDHD is also an independent risk factor for all-cause hospital readmissions and both minor and major complications. LEVEL OF EVIDENCE: III.

Higher revision rates in patients with preoperative contralateral pes planovalgus deformity following total knee arthroplasty.

PURPOSE: The purpose of this study was to compare the incidence of revision in those with pes planovalgus deformity to those without using a large national database. Given the reciprocal changes in lower extremity alignment associated with planovalgus foot deformity, it has been suggested that patients with this deformity has worse outcomes following total knee arthroplasty (TKA). METHODS: A retrospective cohort analysis of patients undergoing elective TKA was conducted using the PearlDiver database. Patients were stratified into three cohorts: those without pes planovalgus, patients with ipsilateral or bilateral pes planovalgus relative to the TKA, and patients with contralateral pes planovalgus. Patients with prior foot reconstructive surgery were excluded. The cohorts were each matched to those without pes planovalgus. Bivariate analysis was performed comparing 90-day medical complications and 2- and 4-year revisions following TKA. An adjusted number needed to be exposed for one additional person to be harmed (NNEH) was calculated using the adjusted odds ratio (OR) and unexposed event rate. RESULTS: Following matched analysis, those with contralateral pes planovalgus had similar odds (OR 3.41; 95% CI 0.93-12.54; p = n.s.) for aseptic revision within 2 years but significantly higher odds (OR 3.35; 95% CI 1.08-10.41; p = 0.03) within 4 years when compared to those without a pes planovalgus deformity. Within 4 years, there was no significant difference in the incidence of aseptic revision (p = n.s.) in patients with ipsilateral/bilateral pes planovalgus. No patients in any cohort underwent septic revision within 4 years of TKA. CONCLUSION: This study found that patients with contralateral pes planovalgus deformity had higher odds of aseptic revision within 4 years following primary TKA in a national database, suggesting that the change in gait kinematics associated with this deformity could possibly be associated with increased revision rates. LEVEL OF EVIDENCE: Level III.

The cost effectiveness of tranexamic acid for preventing periprosthetic joint infection following total shoulder arthroplasty: a break-even analysis.

BACKGROUND: The use of tranexamic acid (TXA) has become widespread in orthopedics to promote hemostasis and has been successfully used to reduce blood loss and infection risk in joint arthroplasty. However, the cost effectiveness of routine TXA use for the prevention of periprosthetic infections in total shoulder arthroplasty remains unknown. METHODS: The acquisition cost of TXA ($5.22) for our institution, along with values from the literature for the average cost of infection-related care ($55,243) and the baseline infection rates for patients without TXA use (0.70%),were used to perform a break-even analysis. The absolute risk reduction (ARR) of infection necessary to justify the prophylactic use of TXA in shoulder arthroplasty was calculated from the nontreated and break-even infection rates. RESULTS: TXA is considered cost-effective if it prevents one infection out of 10,583 total shoulder arthroplasty's (ARR = 0.009%). It is economically justifiable with an ARR range of 0.001% at a cost of $0.50/g to 0.181% at $100/g. At varying costs of infection-related care ($10,000-$100,000) and varying baseline infection rates (0.50%-8.00%) and routine use of TXA remained cost-effective. CONCLUSION: The use of TXA is an economically viable practice for infection prevention following shoulder arthroplasty if it reduces the infection rate by 0.009%. Future, prospective studies should be conducted to observe whether TXA reduces the infection rate by more than 0.009%, showing cost effectiveness.

A Novel Method for Stratification of 30-Day Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Knee Arthroplasty: A National Cohort of 443,157 Patients.

BACKGROUND: Many organizations have used pre-established body mass index (BMI) cut-offs to guide surgical decision-making. As there have been many improvements in patient optimization, surgical technique, and perioperative care over time, it is important to reassess these thresholds and contextualize them to total knee arthroplasty (TKA). The purpose of this study was to calculate data-driven BMI thresholds that predict significant differences in risk of 30-day major complications following TKA. METHODS: Patients who underwent primary TKA from 2010 to 2020 were identified in a national database. Stratum-specific likelihood ratio (SSLR) methodology was used to determine data-driven BMI thresholds at which the risk of 30-day major complications increased significantly. These BMI thresholds were tested using multivariable logistic regression analyses. A total of 443,157 patients were included, who had a mean age of 67 years (range, 18 to 89 years), mean BMI of 33 (range 19 to 59), and 11,766 (2.7%) patients had a 30-day major complication. RESULTS: SSLR analysis identified four BMI thresholds that were associated with significant differences in 30-day major complications: 19 to 33, 34 to 38, 39 to 50, and 51+. When compared to those who had a BMI between 19 and 33, the odds of sustaining a major complication sequentially and significantly increased by 1.1, 1.3, and 2.1 times (P < .05 for all) for the other thresholds. CONCLUSION: This study identified four data-driven BMI strata using SSLR analysis that were associated with significant differences in the risk of 30-day major complications following TKA. These strata can be used to guide shared decision-making in patients undergoing TKA.

Simultaneous Measurement of IgM and IgG Antibodies to SARS-CoV-2 Spike, RBD, and Nucleocapsid Multiplexed in a Single Assay on the xMAP INTELLIFLEX DR-SE Flow Analyzer.

The multiplex capabilities of the new xMAP INTELLIFLEX DR-SE flow analyzer were explored by modifying a serological assay previously used to characterize the IgG antibody to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The goal was to examine the instrument's performance and to simultaneously measure IgM and IgG antibody responses against multiple SARS-CoV-2 antigens in a single assay. Specific antibodies against the SARS-CoV-2 spike (S), receptor binding domain (RBD), and nucleocapsid (N) proteins were investigated in 310 symptomatic case patients using a fluorescent microsphere immunoassay and simultaneous detection of IgM and IgG. Neutralization potential was studied using the addition of soluble angiotensin-converting enzyme 2 (ACE2) to block antibody binding. A profile extending to 180 days from symptom onset (DFSO) was described for antibodies specific to each viral antigen. Generally, IgM levels peaked and declined rapidly ∼3-4 weeks following infection, whereas S- and RBD-specific IgG plateaued at 80 DFSO. ACE2 more effectively prevented IgM and IgG binding in convalescent cases > 30 DFSO, suggesting those antibodies had greater neutralization potential. This work highlighted the multiplex and multi-analyte potential of the xMAP INTELLIFLEX DR-SE, and provided further evidence for antigen-specific IgM and IgG trajectories in acute and convalescent cases. IMPORTANCE The xMAP INTELLIFLEX DR-SE enabled simultaneous and semi-quantitative detection of both IgM and IgG to three different SARS-CoV-2 antigens in a single assay. The assay format is advantageous for rapid and medium-throughput profiling using a small volume of specimen. The xMAP INTELLIFLEX DR-SE technology demonstrated the potential to include numerous SARS-CoV-2 antigens; future work could incorporate multiple spike protein variants in a single assay. This could be an important feature for assessing the serological response to emerging variants of SARS-CoV-2.

A Multiplex Microsphere IgG Assay for SARS-CoV-2 Using ACE2-Mediated Inhibition as a Surrogate for Neutralization.

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the challenges inherent to the serological detection of a novel pathogen such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Serological tests can be used diagnostically and for surveillance, but their usefulness depends on their throughput, sensitivity, and specificity. Here, we describe a multiplex fluorescent microsphere-based assay, 3Flex, that can detect antibodies to three major SARS-CoV-2 antigens-spike (S) protein, the spike ACE2 receptor-binding domain (RBD), and nucleocapsid (NP). Specificity was assessed using 213 prepandemic samples. Sensitivity was measured and compared to that of the Abbott Architect SARS-CoV-2 IgG assay using serum samples from 125 unique patients equally binned (n = 25) into 5 time intervals (≤5, 6 to 10, 11 to 15, 16 to 20, and ≥21 days from symptom onset). With samples obtained at ≤5 days from symptom onset, the 3Flex assay was more sensitive (48.0% versus 32.0%), but the two assays performed comparably using serum obtained ≥21 days from symptom onset. A larger collection (n = 534) of discarded sera was profiled from patients (n = 140) whose COVID-19 course was characterized through chart review. This revealed the relative rise, peak (S, 23.8; RBD, 23.6; NP, 16.7 [in days from symptom onset]), and decline of the antibody response. Considerable interperson variation was observed with a subset of extensively sampled intensive care unit (ICU) patients. Using soluble ACE2, inhibition of antibody binding was demonstrated for S and RBD, and not for NP. Taking the data together, this study described the performance of an assay built on a flexible and high-throughput serological platform that proved adaptable to the emergence of a novel infectious agent.

A multiplex microsphere IgG assay for SARS-CoV-2 using ACE2-mediated inhibition as a surrogate for neutralization.

The COVID-19 pandemic has highlighted challenges inherent to serological detection of a novel pathogen like SARS-CoV-2. Serological tests can be used diagnostically and for surveillance, but their usefulness depends on throughput, sensitivity and specificity. Here, we describe a multiplex fluorescent microsphere-based assay, 3Flex, that can detect antibodies to three SARS-CoV-2 antigens-spike (S) protein, the spike ACE2 receptor-binding domain (RBD), and nucleocapsid (NP). Specificity was assessed using 213 pre-pandemic samples. Sensitivity was measured and compared to the Abbott™ ARCHITECT™ SARS-CoV-2 IgG assay using serum from 125 unique patients equally binned ( n = 25) into 5 time intervals (≤5, 6 to 10, 11 to 15, 16 to 20, and ≥21 days from symptom onset). With samples obtained at ≤5 days from symptom onset, the 3Flex assay was more sensitive (48.0% vs. 32.0%), but the two assays performed comparably using serum obtained ≥21 days from symptom onset. A larger collection ( n = 534) of discarded sera was profiled from patients ( n = 140) whose COVID-19 course was characterized through chart review. This revealed the relative rise, peak (S, 23.8; RBD, 23.6; NP, 16.7; in days from symptom onset), and decline of the antibody response. Considerable interperson variation was observed with a subset of extensively sampled ICU patients. Using soluble ACE2, inhibition of antibody binding was demonstrated for S and RBD, and not for NP. Taken together, this study described the performance of an assay built on a flexible and high-throughput serological platform that proved adaptable to the emergence of a novel infectious agent.

Broad assessment of bioactivity of a collection of spiroindane pyrrolidines through "cell painting".

A collection of small molecules has been synthesized by composing photo-cycloaddition, C-H functionalization, and N-capping strategies. Multidimensional biological fingerprints of molecules comprising this collection have been recorded as changes in cell and organelle morphology. This untargeted, phenotypic approach allowed for a broad assessment of biological activity to be determined. Reproducibility and the magnitude of measured fingerprints revealed activity of several treatments. Reactive functional groups, such as imines, dominated the observed activity. Two non-reactive candidate compounds with distinct bioactivity fingerprints were identified, as well.