key: cord-0762681-4650vwvy
authors: Lam, Joyce C. M.; Moshi, Grace B.; Ang, Soh H.; Chew, Hui M.; Ng, Qing H.; Madjukie, Andrew; Logeswary, Muthiah
title: Management of COVID‐19‐related paediatric blood samples in a clinical haematology laboratory
date: 2020-05-09
journal: Br J Haematol
DOI: 10.1111/bjh.16721
sha: 7cc9004f4a8717b2812c1219456392f8a7562904
doc_id: 762681
cord_uid: 4650vwvy

There is currently limited knowledge about the transmission risks of the SARS-CoV-2 virus and its associated disease COVID-19 from routine clinical specimens. The first study to be published on the initial 41 cases of COVID-19 infections admitted in Wuhan detected SARS-CoV-2 RNA in the blood of 6/41 (15%) of patients (Huang et. al., 2020) . However, another study conducted on 1070 clinical specimens collected from confirmed COVID-19 patients in China showed the highest positive rates of SARS-CoV-2 from rRT-PCR testing of respiratory specimens such as bronchoalveolar lavage, sputum and nasopharyngeal swabs (32% - 93%). In contrast, only 1% of blood specimens and none of the urine specimens tested positive (Wang et. al., 2020).

There is currently limited knowledge about the transmission risks of the SARS-CoV-2 virus and its associated disease COVID-19 from routine clinical specimens. The first study to be published on the initial 41 cases of COVID-19 infections admitted in Wuhan detected SARS-CoV-2 RNA in the blood of 6/41 (15%) of patients. 1 However, another study conducted on 1 070 clinical specimens collected from confirmed COVID-19 patients in China showed the highest positive rates of SARS-CoV-2 from real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) testing of respiratory specimens such as bronchoalveolar lavage, sputum and nasopharyngeal swabs (32%-93%). In contrast, only 1% of blood specimens and none of the urine specimens tested positive. 2 Although the rates of viraemia appear to be low, it nonetheless poses a risk of potential respiratory transmission to laboratory staff via aerosolization of blood specimens during specimen processing steps such as centrifugation and vortexing. Paediatric specimens pose a particular challenge as automated analysers cannot handle small-volume samples from paediatric-sized tubes, necessitating manual handling of specimens. The Haematology Laboratory at the Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, processes over 130 000 paediatric samples annually. Our laboratory received the first sample from a suspect COVID-19 patient on 22 January 2020 and processed samples from a confirmed COVID-19 patient on 5 February 2020. From January to March 2020, we processed approximately 2 070 samples from paediatric patients with suspected or confirmed COVID-19 infection. In this paper, we describe the specimen management policy for handling and processing COVID-19-related blood samples in our laboratory, and highlight the challenges of working with paediatric samples during this period.

Our laboratory had existing biosafety guidelines for specimen management from patients with emerging respiratory pathogens (SARS-CoV and MERS-CoV). In early January 2020, the Ministry of Health in Singapore alerted healthcare practitioners of the emergence of a novel respiratory infection in Wuhan. 3 Following the announcement, we performed a series of risk assessments based on identification of potential hazards and available laboratory equipment and facilities. Our guidelines were regularly reviewed when documents from the Ministry of Health, Singapore Ministry of Health, Singapore, 4 World Health Organization (WHO) 5 and the Centres for Disease Control and Prevention (CDC) 6 relating to laboratory biosafety when handling COVID-19 specimens became available. We reviewed each test offered in our laboratory and made the decision to either require consultations with the laboratory haematologists for tests with a higher risk profile or not to offer tests which could not be performed safely based on our risk assessments Table I . We redesigned the laboratory workspace such that dedicated analysers closest to the Class II biological safety cabinet (BSC) were used for COVID-related specimens in an area separated from the rest of the laboratory.

Prior to the COVID-19 outbreak, paediatric blood specimens were collected in Becton Dickinson (BD) Microtainer EDTA microtubes (Becton, Dickinson and Company, Franklin Lakes, NJ, USA). However, this required open-mode sampling on the Sysmex XN-1000 (Sysmex Corporation, Kobe, Japan) analyser in use at our laboratory, and would have subjected staff to the risk of aerosol exposure. We had previously performed a validation study using the BD Microtainer MAP (Microtube for Automated Process) Microtube (Becton, Dickinson and Company), which is an alternative collection tube with a membrane cap allowing automated sample piercing and analysis without cap removal. Early on in the outbreak, a decision was made to switch specimen collection tubes to the MAP Microtube, avoiding the need to manually handle specimens in open mode. Paediatric blood samples for coagulation assays are collected in 3Á2% sodium citrate Greiner Bio-One MiniCollectâ 9NC (Greiner Bio-One GmbH, Kremsm€ unster, Austria) tubes. Although the tube has a membrane cap allowing for automated closed-mode analysis, the coagulation analyser in use at our laboratory (STA Compact Max (Diagnostica Stago, Asni eres-sur-Seine, France)) is not equipped with the optional cap-piercing system. Specimens for blood gas analysis are collected in heparinized syringes [Becton Dickinson (BD) A-Line TM Blood Gas Analysis Syringe (Becton, Dickinson and Company).

Even before receiving specimens in the laboratory, close communication with clinical areas is essential to ensure safe correspondence transport and appropriate labelling of specimens. At our institution, a disease outbreak task force (DOTF) was set up to co-ordinate management of suspect and confirmed COVID-19 patients, with representation from the laboratory to design protocols and communicate updates around laboratory-related issues. Specimens had to be double-bagged, labelled appropriately as COVID-19-related specimens and hand-delivered to the laboratory to avoid loss or misplacement of specimens. The pneumatic tube system was not used due to the risk of specimen loss and spillage.

As there were limited supplies of face shields in our institution, a decision was made by hospital management to reserve the use of face shields for clinically high-risk situations, for example procedures involving suctioning of patients with confirmed COVID-19 infections. When handling and processing COVID-19-related blood samples in the laboratory, all staff must don personal protective equipment (PPE) including laboratory coats, disposable gloves, surgical masks and safety goggles which provide a good alternative for protection of the face and mucous membranes. All staff are reminded to practice good hand hygiene after processing samples and before leaving the laboratory. This policy applies round the clock.

All COVID-related specimens are initially handled in the Class II BSC. Samples are carefully removed from specimen bags and manually disinfected with MikrozidâAF (94% Ethanol, Sch€ ulke & Mayr GmbH, Norderstedt, Germany) wipes with a minimum contact time of 2 min. Samples for full blood count are loaded directly into the dedicated Sysmex XN analyser located just beside the BSC. Blood films are manually prepared in the BSC and fixed in 100% methanol for 15 min before automated staining by a Hematek (Siemens Healthcare Diagnostic Products GmbH, Marburg, Germany) stainer. Samples sent for coagulation assays are decapped in the BSC and checked for clots with applicator sticks. The samples are centrifuged using a STI PlasmaPrep (Separation Technology Inc, Sanford, FL, USA) centrifuge located within the BSC. Plasma is then aliquoted into Eppendorf tubes which are packed in a clean biohazard bag and hand-carried to the STA Compact Max coagulation Correspondence analyser for analysis. A splash guard was installed beside the analyser for safe opening of the Eppendorf tubes which are then loaded into the sample drawer of the analyser. Point-ofcare testing for blood gases in paediatric patients at our institution is handled mostly at clinical areas by staff in appropriate PPEs using I-Stat devices (Abbott Point of Care Inc, Chicago, IL, USA). However, specimens for blood gas analysis which includes measurement of the haematocrit (Table I) can also be analysed in the laboratory using the CG8 + cartridge on the I-Stat device, with all analysis performed within the BSC.

All consumables used during processing of COVID-related samples are immediately discarded into the original specimen bags, double-bagged and disposed into a biohazard waste bin. When testing is completed, all specimens are doublebagged with new biohazard bags and stored in a locked container for three days before disposal in the biohazard waste bin. When a suspect patient tests positive for COVID-19 from rRT-PCR of respiratory samples, the Haematology Laboratory is informed by the Molecular Microbiology Laboratory within the same laboratory service. Samples from the patient are retrieved and autoclaved the next working day before disposal. Work surfaces inside the BSC are disinfected with Mikrozidâ AF wipes after each use. The Sysmex XN analyser is decontaminated daily with a proprietary 5% sodium hypochlorite solution (CellClean TM ) when performing daily maintenance and shutdown procedures. The Stago Compact Max analyser is decontaminated weekly with a higher strength of sodium hypochlorite (0Á5%) using the routine maintenance protocol. Biological liquid waste from both analysers is decontaminated with 5% sodium hypochlorite for at least 30 min before disposal.

The management of COVID-related specimens from paediatric patients poses unique challenges. Samples from children need to be collected in small-volume tubes, which may not always be suitable for automated analysis by analysers. Repeated blood sampling is also a challenge in young children, necessitating upfront discussion between clinicians and the laboratory haematologist as to the timing and availability of tests, so that repeated blood-taking procedures are minimized.

It is now recognized that children with COVID-19 infections present with less severe symptoms compared to adults, with a case series of more than 2 000 children reporting that 13% of confirmed cases were asymptomatic. 7 A six-month-old infant with confirmed COVID-19 infection identified through family screening treated at our institution remained asymptomatic despite detectable viraemia. 8 Compared to adults, clinical identification of potential COVID-19-infected children may not be as obvious, adding to the risk of laboratory staff unknowingly handling a blood sample with SARS-CoV-2. This is why we have reiterated to staff in our laboratory on the need to adhere to standard precautions for all samples, including the use of PPE such as laboratory coats, surgical masks, gloves and fastidious attention to hand hygiene. In this letter, we have shared our experience and challenges with management of COVID-19-related blood specimens from paediatric patients, and hope that this can serve as a guide for other laboratories who need to handle similar specimens.

Clinical features of patients infected with 2019 novel coronavirus in Wuhan

Detection of SARS-CoV-2 in different types of clinical specimens

COVID-19 in Singapore -Current experience. Critical global issues that require attention and action

Interim biosafety guidelines for laboratories and personnel handling samples or materials associated with the 2019 novel Coronavirus (2019-nCoV)

World Health Organization (WHO) (12 February 2020) Laboratory biosafety guidance related to the novel coronavirus

Centres for Disease Control and Prevention (CDC) Interim Laboratory Biosafety Guidelines for Handling and Processing Specimens Associated with Coronavirus Disease 2019 (COVID-19)

Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China

A well infant with Coronavirus disease 2019 (COVID-19) with high viral load

All authors contributed to the drafting of the COVID-19-related biosafety guidelines in use in our laboratory and to the writing of the manuscript. All authors approved the submitted version and revisions. We acknowledge Dr Clement Ho and Mr Setoh Johnson for their help with the manuscript.