Mining the Gap: Deriving Pregnancy Reference Intervals for Hematology Parameters Using Clinical Datasets.

BACKGROUND: Physiological changes during pregnancy invalidate use of general population reference intervals (RIs) for pregnant people. The complete blood count (CBC) is commonly ordered during pregnancy, but few studies have established pregnancy RIs suitable for contemporary Canadian mothers. Prospective RI studies are challenging to perform during pregnancy while retrospective techniques fall short as pregnancy and health status are not readily available in the laboratory information system (LIS). This study derived pregnancy RIs retrospectively using LIS data linked to provincial perinatal registry data. METHODS: A 5-year healthy pregnancy cohort was defined from the British Columbia Perinatal Data Registry and linked to laboratory data from two laboratories. CBC and differential RIs were calculated using direct and indirect approaches. Impacts of maternal and pregnancy characteristics, such as age, body mass index, and ethnicity, on laboratory values were also assessed. RESULTS: The cohort contained 143 106 unique term singleton pregnancies, linked to >972 000 CBC results. RIs were calculated by trimester and gestational week. Result trends throughout gestation aligned with previous reports in the literature, although differences in exact RI limits were seen for many tests. Trimester-specific bins may not be appropriate for several CBC parameters that change rapidly within trimesters, including red blood cells (RBCs), some leukocyte parameters, and platelet counts. CONCLUSIONS: Combining information from comprehensive clinical databases with LIS data provides a robust and reliable means for deriving pregnancy RIs. The present analysis also illustrates limitations of using conventional trimester bins during pregnancy, supporting use of gestational age or empirically derived bins for defining CBC normal values during pregnancy.

Evaluation of observed and unobserved self-collection of saline gargle samples for the detection of SARS-CoV-2 in outpatients.

The diagnostic sensitivity of observed and unobserved self-collected saline gargle samples for the molecular detection of SARS-CoV-2 in adults and school-aged children was evaluated against a reference standard of health care worker collected nasopharyngeal flocked swab. A total of 46 participants had a positive nasopharyngeal swab sample; of these, 10 were in the observed phase and 36 were in the unobserved phase. Only one matching saline gargle sample tested negative and this was in the unobserved phase, giving an overall sensitivity of 98%. Average viral target Ct values were higher in the saline gargle samples. RNaseP Ct values were lower in unobserved collected samples compared to observed collected samples. Unobserved self-collection of saline gargle samples is a promising outpatient testing method for COVID-19 diagnosis. The self-collection method has potential to simplify the diagnostic cycle and facilitate implementation of COVID-19 testing, particularly in settings with limited access to health care workers.

Biobank Awareness Changes Opinions of Adolescents and Parents on Participation and Practices.

To evaluate barriers and facilitators of pediatric biobank participation, we studied whether increased awareness of participants about pediatric biobanking changes their opinions on biobanking practices and their willingness to participate in biobanks. Adolescents (14-18 years) in public schools and their parents were invited to participate in a survey either with or without viewing educational material about biobanking before completing the survey. Questions included willingness to donate, consenting practices and use of specimens. Surveys were administered. Nonparametric statistical tests (Mann-Whitney U) were used to test the significance of differences in Likert scale responses between participant groups. A total of 545 participants (219 adolescent and 176 parents with prior awareness about biobanking vs. 106 adolescents and 44 parents without) completed the survey. Participants who had participated in an educational session were more willing to donate compared to participants without this session under three different conditions: a left-over sample, an extra sample at the time of a medical procedure, and an extra procedure. Adolescents without prior awareness were significantly more willing to donate compared to their parents. Parents perceived the need for reconsent more important than children, although it was less important to educated parents versus noneducated parents. Age of assent was lower in the groups with prior awareness and ongoing use of specimens without reconsent was more permissible to these participants. In conclusion, prior awareness of biobanks may facilitate pediatric biobank participation.

Self-Collected Saline Gargle Samples as an Alternative to Health Care Worker-Collected Nasopharyngeal Swabs for COVID-19 Diagnosis in Outpatients.

We assessed the performance, stability, and user acceptability of swab-independent self-collected saliva and saline mouth rinse/gargle sample types for the molecular detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in adults and school-aged children. Outpatients who had recently been diagnosed with COVID-19 or were presenting with suspected COVID-19 were asked to have a nasopharyngeal (NP) swab collected and provide at least one self-collected sample type. Participants were also asked about sample acceptability using a five-point Likert scale. For those previously diagnosed with COVID-19, all samples underwent real-time PCR testing using a lab-developed assay, and the majority were also tested using an FDA-authorized assay. For those presenting with suspected COVID-19, only those with a positive nasopharyngeal swab sample went on to have other samples tested. Saline mouth rinse/gargle and saliva samples were tested daily at time zero, day 1, and day 2 to assess nucleic acid stability at room temperature. Fifty participants (aged 4 to 71 years) were included; of these, 40 had at least one positive sample and were included in the primary sample yield analysis. Saline mouth rinse/gargle samples had a sensitivity of 98% (39/40), while saliva samples had a sensitivity of 79% (26/33). Both saline mouth rinse/gargle and saliva samples showed stable viral RNA detection after 2 days of room temperature storage. Mouth rinse/gargle samples had the highest (mean, 4.9) and health care worker (HCW)-collected NP swabs had the lowest acceptability scores (mean, 3.1). In conclusion, saline mouth rinse/gargle samples demonstrated higher combined user acceptability ratings and analytical performance than saliva and HCW-collected NP swabs. This sample type is a promising swab-independent option, particularly for outpatient self-collection in adults and school-aged children.

Opinions of Adolescents and Parents About Pediatric Biobanking.

PURPOSE: A biobank is defined as "a facility for the collection, preservation, storage and supply of biological samples and associated data, which follows standardized operating procedures and provides material for scientific and clinical use." The practice of biobanking must consider the best interests of participants, which is especially complicated in the pediatric setting, where parents or guardians are responsible for consent of their children. Age of participant assent, consent, and reconsent at the age of majority are some of the issues which need to be addressed. METHODS: We conducted an exploratory survey of four cohorts: (1) adolescents aged 14-18 years treated at British Columbia Children's Hospital, Vancouver, British Columbia, Canada, in the Division of Oncology, Cardiology, or Orthopedics. (2) Parents of the adolescents described in (1). (3) Adolescents aged 14-18 years from high schools in Vancouver, British Columbia, Canada. (4) Parents of the adolescents described in (3). RESULTS: We show that clinic participants rated a higher willingness to donate specimens versus school participants. Furthermore, clinic participants felt assent was more important and parental consent alone was insufficient. The median suggested age for assent was 14.5 years among adolescent responses and 16 years from parental responses of both groups. School parents were the most conservative in their responses toward their child's participation in a biobank. CONCLUSIONS: Adolescents, who were seen in clinics and their parents, had a more altruistic approach toward pediatric biobanking than those surveyed in the school setting. Additionally, parents are less comfortable making decisions regarding biobanking than their adolescent children.