SARS-CoV-2 antibody changes in patients receiving COVID-19 convalescent plasma from normal and vaccinated donors.

Vaccination has been shown to stimulate remarkably high antibody levels in donors who have recovered from COVID-19. Our objective was to measure patient antibody levels before and after transfusion with COVID-19 Convalescent Plasma (CCP) and compare the antibody levels following transfusion of CCP from vaccinated and nonvaccinated donors. Plasma samples before and after transfusion were obtained from 25 recipients of CCP and COVID-19 antibody levels measured. Factors that effect changes in antibody levels were examined. In the 21 patients who received CCP from nonvaccinated donors, modest increases in antibody levels were observed. Patients who received two units were more likely to seroconvert than those receiving just one unit. The strongest predictor of changes in patient antibody level was the CCP dose, calculated by the unit volume multiplied by the donor antibody level. Using patient plasma volume and donor antibody level, the post-transfusion antibody level could be predicted with reasonable accuracy(R2> 0.90). In contrast, the 4 patients who received CCP from vaccinated donors all had dramatic increases in antibody levels following transfusion of a single unit. In this subset of recipients, antibody levels observed after transfusion of CCP were comparable to those seen in donors who had fully recovered from COVID-19. If available, CCP from vaccinated donors with very high antibody levels should be used. One unit of CCP from vaccinated donors increases patient antibody levels much more than 1 or 2 units of CCP from unvaccinated donors.

Exponential increase in neutralizing and spike specific antibodies following vaccination of COVID-19 convalescent plasma donors.

BACKGROUND: With the recent approval of COVID-19 vaccines, recovered COVID-19 subjects who are vaccinated may be ideal candidates to donate COVID-19 convalescent plasma (CCP). CASE SERIES: Eleven recovered COVID-19 patients were screened to donate CCP. All had molecularly confirmed COVID-19, and all but one were antibody positive by chemiluminescence immunoassay (DiaSorin) prior to vaccination. All were tested again for antibodies 11-21 days after they were vaccinated (Pfizer/Moderna). All showed dramatic increases (~50-fold) in spike-specific antibody levels and had at least a 20-fold increase in the IC50 neutralizing antibody titer based on plaque reduction neutralization testing (PRNT). The spike-specific antibody levels following vaccination were significantly higher than those seen in any non-vaccinated COVID-19 subjects tested to date at our facility. CONCLUSION: Spike-specific and neutralizing antibodies demonstrated dramatic increases following a single vaccination after COVID-19 infection, which significantly exceeded values seen with COVID-19 infection alone. Recovered COVID-19 subjects who are vaccinated may make ideal candidates for CCP donation.

Accidental intoxications in toddlers: lack of cross-reactivity of vilazodone and its urinary metabolite M17 with drug of abuse screening immunoassays.

BACKGROUND: Vilazodone is an FDA approved medication used to treat major depressive disorder. The authors describe two cases of accidental vilazodone exposure in toddlers who presented with symptoms similar to amphetamine exposure and also with unexplained positive amphetamine urine immunoassay drug screens. Given a lack of published data on cross-reactivity of vilazodone and its metabolites with drug of abuse screening tests, the authors investigated drug of abuse immunoassay cross-reactivity of vilazodone and metabolites using computational and empirical approaches. METHODS: To ascertain the likelihood that vilazodone would cross-react with drug of abuse screening immunoassays, the authors assessed the two-dimensional (2D) similarity of the vilazodone parent molecule and known metabolites to an array of antigenic targets for urine immunoassay drug screens. To facilitate studies of the commercially unavailable M17 metabolite, it was prepared synthetically through a novel scheme. Urine and serum were spiked with vilazodone and M17 into urine (200-100,000 ng/mL) and serum (20-2000 ng/mL) samples and tested for cross-reactivity. RESULTS: Computational analysis using 2D similarity showed that vilazodone and metabolites have generally low similarity to antigenic targets of common drug of abuse screening immunoassays, predicting weak or no cross-reactivity. The M17 metabolite had 2D similarity to amphetamines and tricyclic antidepressants in a range similar to some other compounds exhibiting weak cross-reactivity on these immunoassays. Cross-reactivity testing was therefore performed on two different urine amphetamines immunoassays and a serum tricyclic antidepressant immunoassay. However, actual testing of cross reactivity for vilazodone and the M17 metabolite did not detect cross-reactivity for any urine amphetamines screen at concentrations up to 100,000 ng/mL and for a serum tricyclic antidepressants assays at concentrations up to 2000 ng/mL. CONCLUSION: While the vilazodone metabolite M17 has weak 2D structural similarity to amphetamines and tricyclic antidepressants, the current study did not demonstrate any experimental cross-reactivity with two different urine amphetamines immunoassays and a serum tricyclic antidepressant immunoassay. Vilazodone ingestions in young children present a diagnostic challenge in their similarity to amphetamine ingestions and the lack of routine laboratory tests for vilazodone. Further work is needed to understand the metabolic profile for vilazodone in children versus adults.

Therapeutic Drug Monitoring of Pentobarbital: Experience at an Academic Medical Center.

BACKGROUND: Pentobarbital is used for management of intractable seizures and for reducing elevated intracranial pressure. Dosing of pentobarbital can be aided by therapeutic drug monitoring (TDM). There is no commercially available automated assay for measurement of pentobarbital serum/plasma concentrations; consequently, chromatography-based assays are often used. METHODS: Pentobarbital TDM was studied over a 14-year period at an academic medical center. 154 patients (94 adult, 60 pediatric) were identified who had pentobarbital levels ordered at least once during a hospital encounter. Chart review included patient diagnosis, indication for pentobarbital therapy, recent or concomitant medication with other barbiturates, patient disposition, organ donation, pentobarbital dosing changes, and neurosurgical procedures. Pentobarbital serum/plasma concentrations were determined on an automated clinical chemistry platform with a laboratory-developed test adapted from a urine barbiturates immunoassay. RESULTS: Chart review showed therapeutic use of pentobarbital generally consistent with previously published literature. The most common errors observed involved confusion in barbiturate names (eg, mix-up of pentobarbital and phenobarbital in test ordering or in provider notes) that seemed to have minimal impact on TDM effectiveness, with pentobarbital serum/plasma concentrations generally within target ranges. The laboratory-developed pentobarbital immunoassay showed cross-reactivity with phenobarbital and butalbital that was eliminated by alkaline and heat pretreatment. The immunoassay was linear to 20 mcg/mL and correlated closely with gas chromatography-mass spectrometry measurements at a reference laboratory. CONCLUSIONS: Pentobarbital TDM can be performed by immunoassay on an automated clinical chemistry platform, providing an alternative to chromatography-based methods. Confusion in barbiturate names is common, especially pentobarbital and phenobarbital.

Head-to-Head Comparison of Two SARS-CoV-2 Serology Assays.

BACKGROUND: While molecular techniques remain the gold standard for diagnosis of acute SARS-CoV-2 infection, serological tests have the unique potential to ascertain how much of the population has been exposed to the COVID-19 pathogen. There have been limited published studies to date documenting the performance of SARS-CoV-2 antibody assays. METHODS: We compared the DiaSorin Liaison SARS-CoV-2 S1/S2 IgG and Roche Diagnostics Elecsys Anti-SARS-CoV-2 assays using 228 samples spanning patients with positive PCR for SARS-CoV-2, patients with compatible symptoms but negative PCR, pre-COVID specimens, and potential cross-reactives. RESULTS: Both assays detected antibodies in 18/19 samples collected at least one week after a positive PCR result. Neither method consistently detected antibodies in specimens collected within one week of a positive PCR result (sensitivity < 50%), but antibodies were detected by only Roche in four samples in this time frame. Using 139 pre-COVID and 35 PCR-negative samples, the Roche and DiaSorin assays demonstrated specificities of 100.0% and 98.9%, respectively. Neither assay demonstrated cross-reactivity from other coronaviruses (229E, HKU1, NL63, OC43), respiratory pathogens (adenovirus, metapneumovirus, rhinovirus/enterovirus), or antibodies to other viruses (HIV, EBV, CMV, HBV, HCV, HAV). DISCUSSION: Overall, the qualitative interpretations afforded by the Roche and DiaSorin assays agreed for 97% of samples evaluated. Minor discrepancies in sensitivity and specificity were observed between methods, with the differences in specificity more clinically significant for our low-prevalence population. For the DiaSorin assay, all disagreements with the Roche assay occurred in samples with quantitative signals near the cut-off determining positivity.

Telepsychiatry in Obstetrics.

Each year in the United States, approximately half a million reproductive-aged women are afflicted with major depression. Pregnant and postpartum women can be reluctant to openly disclose their suffering related to depression and other stigmatizing illnesses (eg, mood and anxiety disorders, posttraumatic stress disorder, and substance use disorders) and subsequently remain symptomatic with no relief. Maternal mortality related to these conditions is significant, with maternal suicide and overdose-related death peaking between 7 and 12 months postpartum. Geographic challenges in accessing perinatal mental health experts can be overcome through the use of telepsychiatry services using a secure video platform (telemedicine).

Impact of Daylight Saving Time on the Clinical Laboratory.

Daylight saving time is a practice in some countries and local regions to set clocks forward (typically 1 hour) during the longer days of summer and back again in autumn. Time changes resulting from daylight saving time have the potential to impact clinical laboratory instruments, computer interfaces, and information systems. We analyzed turnaround time data for an academic medical center clinical laboratories (chemistry, hematology, blood gas analyzer, and transfusion medicine), examining how turnaround time was impacted by the daylight saving time shifts in 2017. We also determined whether the daylight saving time shift on November 5, 2017 ("fall back" by 1 hour) resulted in any "absurd" time combinations such as a receipt time occurring "before" a normally later time such as final result. We also describe challenges resulting from daylight saving time changes over a 5-year period. The only significant impact on turnaround time was for clinical chemistry samples during the autumn daylight saving time change, but the overall impact was low. Four instances of absurd time combinations occurred in the autumn time change with only a transfusion medicine example resulting in an interface error (a Type and Screen resulted "before" receipt in laboratory). Over a 5-year period, other daylight saving time impacts included problems of reestablishing interface to instruments, inadvertent discrepancies in manual time changes at different points of the core laboratory automation line, and time change errors in instruments with older operating systems lacking patches that updated daylight saving time rules after 2007. Clinical laboratories should be aware that rare problems may occur due to issues with daylight saving time changes.

Use of a Rapid Ethylene Glycol Assay: a 4-Year Retrospective Study at an Academic Medical Center.

Ethylene glycol (EG) is a common cause of toxic ingestions. Gas chromatography (GC)-based laboratory assays are the gold standard for diagnosing EG intoxication. However, GC requires specialized instrumentation and technical expertise that limits feasibility for many clinical laboratories. The objective of this retrospective study was to determine the utility of incorporating a rapid EG assay for management of cases with suspected EG poisoning. The University of Iowa Hospitals and Clinics core clinical laboratory adapted a veterinary EG assay (Catachem, Inc.) for the Roche Diagnostics cobas 8000 c502 analyzer and incorporated this assay in an osmolal gap-based algorithm for potential toxic alcohol/glycol ingestions. The main limitation is that high concentrations of propylene glycol (PG), while readily identifiable by reaction rate kinetics, can interfere with EG measurement. The clinical laboratory had the ability to perform GC for EG and PG, if needed. A total of 222 rapid EG and 24 EG/PG GC analyses were documented in 106 patient encounters. Of ten confirmed EG ingestions, eight cases were managed entirely with the rapid EG assay. PG interference was evident in 25 samples, leading to 8 GC analyses to rule out the presence of EG. Chart review of cases with negative rapid EG assay results showed no evidence of false negatives. The results of this study highlight the use of incorporating a rapid EG assay for the diagnosis and management of suspected EG toxicity by decreasing the reliance on GC. Future improvements would involve rapid EG assays that completely avoid interference by PG.

Ordering of the Serum Angiotensin-Converting Enzyme Test in Patients Receiving Angiotensin-Converting Enzyme Inhibitor Therapy: An Avoidable but Common Error.

BACKGROUND: Serum angiotensin-converting enzyme (ACE) levels may be decreased by use of ACE inhibitor (ACEI) medication. In this study, we determined how often ACE levels were measured in patients receiving ACEI therapy. METHODS: ACE levels analyzed over a 54-month preintervention time period at an academic medical center were reviewed retrospectively for tests performed during ACEI therapy. These data were compared with a large, deidentified dataset of ACE levels measured at a national reference laboratory; in vitro studies of ACEI inhibition; and liquid chromatography time-of-flight mass spectrometry detection of lisinopril in a subset of clinical specimens. RESULTS: Over a 54-month period, 1,292 patients had ACE levels measured, with 108 patients (8.4%) receiving ACEI therapy at the time of testing. ACE levels measured for patients receiving ACEI therapy were substantially lower. In general, clinical teams did not recognize a medication effect on ACE levels. Introduction of a warning prompt in the electronic health record reduced the ordering of ACE levels in patients receiving ACEIs by > 60% in a 17-month postintervention time period. The deidentified dataset of ACE levels at a reference laboratory showed a bimodal distribution, with a peak of very low ACE levels. Using liquid chromatography time-of-flight mass spectrometry, the presence of lisinopril was confirmed in a subset of specimens with low ACE activity. In vitro studies of two different ACE assays showed significant inhibition of activity at clinically relevant concentrations. CONCLUSIONS: Assessment of ACE activity is often measured for patients receiving ACEIs, potentially leading to low ACE concentrations and inaccurate interpretations.

A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography.

A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, isopropanol, ethylene glycol, and propylene glycol on a single instrument with rapid switch-over from alcohols to glycols analysis. In addition to the novel HS-GC method, a retrospective analysis of patient specimens containing ethylene glycol and propylene glycol was also described. A total of 36 patients ingested ethylene glycol, including 3 patients who presented with two separate admissions for ethylene glycol toxicity. Laboratory studies on presentation to hospital for these patients showed both osmolal and anion gap in 13 patients, osmolal but not anion gap in 13 patients, anion but not osmolal gap in 8 patients, and 1 patient with neither an osmolal nor anion gap. Acidosis on arterial blood gas was present in 13 cases. Only one fatality was seen; this was a patient with initial serum ethylene glycol concentration of 1282 mg/dL who died on third day of hospitalization. Propylene glycol was common in patients being managed for toxic ingestions, and was often attributed to iatrogenic administration of propylene glycol-containing medications such as activated charcoal and intravenous lorazepam. In six patients, propylene glycol contributed to an abnormally high osmolal gap. The common presence of propylene glycol in hospitalized patients emphasizes the importance of being able to identify both ethylene glycol and propylene glycol by chromatographic methods.