A performance evaluation of chemiluminescence enzyme immunoassays on the Sysmex CN-6500 haemostasis analyser.

BACKGROUND: The Sysmex CN-6500 is a new haemostasis analyser with an integrated immunoassay module that performs chemiluminescence enzyme assay (CLEIA) in addition to coagulation, turbidimetric, chromogenic and platelet aggregation tests. AIMS: To evaluate the analytical performance of the CN-6500 against the predicate device (Sysmex HISCL-800) for soluble thrombomodulin (TM), thrombin-antithrombin (TAT), tissue plasminogen activator/plasminogen activator inhibitor 1 complex (tPAI-C) and plasmin α2 plasmin inhibitor complex (PIC) assays. METHODS: Imprecision was assessed by testing two levels of quality control plasmas 10 times on 5 separate days. Comparability was studied in 230 plasmas from normal donors (n = 30), patients with suspected disseminated intravascular coagulation (DIC, n = 100), sepsis (n = 20) or liver disease (n = 20), lipaemic (n = 20), haemolysed (n = 20) and icteric samples (n = 20). Limit of detection, limit of quantitation and linearity were determined by testing serial dilutions of normal plasma. Sample carryover was assessed by testing samples with high and low normal levels of the analytes concerned. RESULTS: The CN-6500 performed 21 CLEIA tests per hour, while simultaneously performing coagulation tests. Acceptable between-run imprecision was obtained using commercial controls with normal and high activity for each analyte (%CV <4%), for all four assays. Excellent linearity was observed (slope 0.89-1.03; r2 >0.99) across the measurement range. The lower limits of detection and quantitation were as follows: TM <0.3/0.6 TU/ml, TAT >0.1/<0.2 ng/ml, PIC <0.004/<0.008 µg/ml and tPAI-C < 0.01/<0.1 ng/ml, respectively. All four assays showed excellent correlation between analysers and were unaffected by haemolysis, icterus or lipaemia. No carryover was observed. CONCLUSIONS: Our data demonstrate that the performance of the CLEIA assays on the CN-6500 is comparable to that of a stand-alone immunoassay analyser.

What is Thy3a? A study of 336 Thy3a (AUS/FLUS) thyroid FNAs with histology compares UK RCPath with other reporting systems and shows how Thy3a subclassification can improve risk stratification and help address overuse of this category.

INTRODUCTION: Thy3a (AUS/FLUS) is an indeterminate and heterogeneous category in thyroid cytology. Thy3a reporting rates vary widely, with many laboratories documenting overuse. Subclassification of Thy3a helps with risk stratification. We aimed to investigate whether subclassification can also help address Thy3a overuse. We compare the UK reporting system with other terminologies. METHODS: An audit of thyroid fine needle aspirations (FNAs) reported at our institution between 2012 and 2017 was performed. Thy3a FNAs followed by histology were reviewed and subcategorised into four subgroups: Scanty Atypia (SA), Scanty Microfollicular (SMF), Favour Benign (FB) and Thyroiditis versus Neoplasm (TVN). Review and subclassification were blinded to histology outcomes. FNAs were correlated with histology and statistical analysis was performed. RESULTS: Our Thy3a rate was high (24% of all thyroid FNAs). For 336 Thy3a FNAs with histology, the malignancy rates of the four subgroups were: SA 68%, SMF 20%, FB 4%, TVN 31%. There were significant associations between subgroup and malignancy risk, and between subgroup and tumour risk. On histology, SA had more malignancies than expected and FB had fewer. SA and SMF had more tumours than expected and FB had fewer. SMF and Thy3f FNAs were similar in terms of tumour and malignancy outcomes. CONCLUSIONS: Subclassification of Thy3a FNAs into these four subgroups is recommended. This can improve risk stratification and help address overuse of Thy3a. We propose that some FB and SMF cases could be safely diverted to Thy2 and Thy3f respectively. We compare various reporting terminologies and question how indeterminate FNAs should be classified.

A comparative evaluation of the CN-6000 haemostasis analyser using coagulation, amidolytic, immuno-turbidometric and light transmission aggregometry assays.

BACKGROUND: The CN-6000 (Sysmex Corp.) is a new haemostasis analyser with blood coagulation, amidolytic, immuno-turbidometric and light transmission aggregometry (LTA) capabilities. Transmitted light is monitored at multiple wavelengths (340, 405, 575, 660, 800 nm), from an LED light source. AIMS: To evaluate the performance of the CN-6000 against a predicate device. METHODS: The CN-6000 was evaluated against the CS-5100 (Sysmex) for 14 different tests, using 880 samples from normal subjects, anticoagulated patients, critically ill patients, plasmas with high or low fibrinogen content or abnormal levels of interfering substances. Between-day assay imprecision was assessed using commercial QC materials (n = 10 replicates on each of 5 days). RESULTS: Acceptable levels of imprecision were obtained for all assays. Agreement between the two analysers was excellent for all assays. Throughput was 35% higher using the CN-6000 (337 vs 250 tests per hour for PT, aPTT and fibrinogen). The CN-6000 also demonstrated improved clot detection in plasmas with high levels of interfering substances as demonstrated by a 29% reduction in "vote-outs" due to low light transmission (24 vs 34). CONCLUSIONS: The CN-6000 demonstrated excellent comparability with the predicate instrument and acceptable levels of imprecision in all assays. Improvements in throughput and clot detection in the presence of interfering substances were also shown.

A practical method for reducing the interference due to lipaemia in coagulation tests.

INTRODUCTION: Plasma samples with gross lipaemia present a challenge for coagulation laboratories using optical analysers. High-speed centrifugation may be used to remove excess lipids but it has not established whether this affects haemostasis tests. The aims were to determine whether the removal of lipid by centrifugation affects PT, APTT, fibrinogen, D-dimer and von Willebrand factor activity measurements. METHODS: Twenty-six lipaemic samples (median [range]): triglyceride 4.6 mmol/L [0.5-17.0]; cholesterol: 4.06 mmol/L [2.20-9.41] and 20 plasmas spiked with Intralipid 20 or lipid isolated from patient plasmas (median triglyceride of 11.95 mmol/L [5.0-17.0] and cholesterol 4.33 [3.22-7.06]), were tested before and after the removal of the lipid layer by centrifugation (10000 g for 10 minutes). Tests were performed using the CS-5100 (Sysmex) coagulation analyser. RESULTS: Thirteen, 9, 3 and 1 of the lipaemic or spiked samples failed to give PT, APTT, fibrinogen and D-dimer results, respectively. Centrifugation significantly reduced triglyceride (median 2.7, [0-6.1 mmol/L]) and cholesterol (median 0.52 [0-3.5]), allowing clot detection in all tests. There were no statistically significant differences in fibrinogen, D-dimer or VWF levels in samples before and after lipid removal. A small but clinically insignificant change in PT and APTT was observed after lipid removal. CONCLUSION: High-speed centrifugation reduces lipaemia sufficiently to allow testing on an optical coagulation analyser without introducing clinically significant differences PT, APTT, fibrinogen, D-dimer or VWF activity values.

The value of the white precursor cell channel (WPC) on the Sysmex XN-1000 analyser in a specialist paediatric hospital.

BACKGROUND: Historically, haematology analyser flags for abnormal white blood cells (WBCs) show good sensitivity but lower specificity, causing unnecessary blood film reviews. While the WBC differential channel on Sysmex XE and XN instruments reports a combined flag for blasts/abnormal lymphocytes, the new white precursor cell channel (WPC) on the XN series has been introduced to separate this into a specific flag for either cell type or, if no abnormality, remove the flag entirely. AIMS: To compare the efficiency of abnormal WBC flags from the XN WPC to our existing analyser and determine whether WPC can reduce false positive flags and blood films required. METHODS: Abnormal WBC flags from the Sysmex XE-5000 and XN-1000 were compared to manual differential and blood film morphology on 300 K2EDTA samples from infants and children. RESULTS: The XN WPC flag for blasts was more sensitive and specific than flags indicating blasts on the XE-5000, with a reduction in false positives from 64% (XE) to 36% (XN). Overall efficiency of the WPC flag for abnormal lymphocytes was 94% vs 79% on the XE. WPC reduced false positive flags for blasts and abnormal lymphocytes on neonatal samples by 50%. Automatic reflex analysis by WPC correctly removed a false positive flag from the white cell differential channel on 46% of samples. Total abnormal WBC flags from XN WPC were less (73) than the XE-5000 (92). CONCLUSIONS: XN WPC demonstrated superior efficiency of abnormal WBC flags on paediatric samples, compared to the XE-5000, with greater sensitivity and specificity of flagging, reducing blood films for review.

How to do it: the difficult thyroid.

There is a paucity of publications detailing how to deal with the difficult thyroid cancer. When compared to other cancers, it is relatively rare with several histopathological subtypes which run differing clinical courses and respond to different therapies. It is a condition predominately treated by specifically trained General and now ENT surgeons who already have a thorough knowledge of vocal fold assessment and rehabilitation as well as emergency airways management both to avoid and treat common complications should they occur.Good surgery involves a team effort to produce good results consistently. All members of the team are essential to quality service delivery. Communication with the team and the patient is paramount. We describe our approach to the difficult thyroid.

Use of gel caps to aid endoscopic insertion of nasogastric feeding tubes: a comparative audit.

INTRODUCTION: Nutrition is crucial to successful outcomes in peri-operative head and neck cancer patients. Nasogastric feeding tubes are an accepted and safe method of providing enteral nutrition in the short-term. Many methods have been advocated for successfully inserting and securing nasogastric tubes and each practitioner will have his or her preferred technique. OBJECTIVES: To confirm the effectiveness of using gel caps combined with the flexible nasendoscope for the insertion of nasogastric feeding tubes in head and neck cancer patients following failure of traditional methods. PARTICIPANTS: Thirty-five consecutive patients requiring nasogastric feeding tubes were included in this comparative audit. All had failed traditional insertion methods after 2 attempts and were therefore eligible for inclusion. Patients were randomised to undergo attempted insertion with the flexible nasendoscope with or without the use of a gel cap (both methods have been previously described). AUDIT OUTCOME: Primary outcome measures showed no significant difference between the two techniques. DISCUSSION: We found the methodology to be of no greater benefit to our patients when compared to our alternative current practice for failed blind nasogastric tube insertion. We retain this methodology in our armamentarium for difficult circumstances but have continued with our standard practice for most patients needing nasogastric tube placement.

Diathermy in perioperative practice.

Diathermy has revolutionised modern surgery and is an important tool for efficient and safe surgical practice. It has evolved to become the modern day scalpel, being used for cutting and coagulating tissues. This article addresses the functioning and safe use of diathermy in the perioperative setting. The various precautionary checks before surgery, which are prerequisite for safe usage, are highlighted along with the necessary safety drills during and after operation. A specific note is included about the use of electrical equipment in specialised surgeries like cardiac and laparoscopic surgery. The issues regarding the maintenance and repair of equipment are acknowledged and finally, the anticipation for a future with precise and safer cutting and coagulation devices is addressed.