Telephone assessment of new hernia referrals-is it possible?

PURPOSE

Utilisation of remote clinics is increasing in healthcare settings worldwide. During the height of the COVID pandemic, our UK-based teaching hospital has trialled telephone assessment for new patients presenting with primary hernias. Selected cases are listed for elective repair of primary hernia direct from telephone clinic assessment. In March 2021, after this process had been in place for 13 months, departmental triage criteria were introduced, allocating patients to initial assessment in Face to Face or Telephone Clinics. Here, we evaluate the effectiveness of telephone assessment, with specific attention to 'Day of Surgery' cancellation. We also assess the effect of our triage criteria on rate of 'Day of Surgery' cancellation.

METHODS

Departmental diaries were studied retrospectively to identify patients listed for hernia repair between February 2020 and February 2022. Data were obtained from clinic letters, discharge paperwork and operating lists, as well as from management teams. Fishers Exact test was used to compare groups seen either face to face or remotely as well and pre- and post-intervention.

RESULTS

325 patients were listed for hernia repair, 56 after telephone assessment. 6 (11%) of those listed from telephone clinic were cancelled on the day of surgery, compared with 34 (13%) of those seen face to face. With triage criteria in place, listing from telephone clinic increased significantly from 14 to 27%. Overall day of surgery cancellations reduced from 13 to 9%. Rate of day of surgery cancellation in those assessed in telephone clinic reduced from 12 to 9%.

CONCLUSIONS

There is no significant difference between day of surgery cancellations after face to face or telephone clinic assessment. Triage criteria for telephone assessment appear to increase the numbers being listed after remote clinics. This did not significantly impact the number of day of surgery cancellations.

Pancreatoduodenectomy for suspected malignancy: nonmalignant histology confers increased risk of serious morbidity

BACKGROUND/AIMS

A tissue diagnosis is not always obtained prior to pancreatoduodenectomy (PD) and a proportion of patients are found to have noncancerous histology postoperatively. It is unknown if these patients have different outcomes when compared with those who have malignancy confirmed.

METHODS

A retrospective paired case matched control study was undertaken. Patients who underwent PD for suspected malignancy but ultimately had nonmalignant histology were identified. Each was matched to a confirmed malignant control using the following criteria: age, gender, body mass index, American Society of Anesthesiologists grade, neoadjuvant treatment, preoperative serum bilirubin, preoperative biliary stenting and type of pancreatic anastomosis. Matching was blinded to the measured outcomes, which included perioperative morbidity and mortality.

RESULTS

Forty-five cases were compared with 45 well-matched controls. There was no difference in 30- or 90-day mortality, or length of stay. While overall morbidity rates were the same, patients with nonmalignant disease were more likely to experience major (Clavien-Dindo grade III-IV) morbidity (40.0% versus 17.8%, p = 0.0352). Independently, rates of clinically relevant pancreatic fistula (CR-POPF) were higher in the nonmalignant group (22.2% versus 4.44%, p = 0.0131).

CONCLUSIONS

In our study, PD patients with nonmalignant histology had significantly higher incidence of major morbidity and CR-POPF when compared with those who had malignancy confirmed. This should be considered when planning the management of patients with known or presumed benign/premalignant disease.

Anatomy of the vesicovaginal fascia and its relation to branches of the inferior hypogastric plexus

The inferior hypogastric plexus (IHP) lies in the extraperitoneal pelvis, and supplies branches to pelvic and perineal viscera. In men, the rectoprostatic fascia (Denonvillier's fascia) forms a distinct double fascial layer between the seminal glands and the rectum. The hypogastric nerve projections to the prostate and seminal glands run anterior to this. An analagous fascial layer in women between the vagina and cervix posteriorly and the urinary bladder anteriorly has recently been described. The purpose of this study was to examine the anatomy of the vesicovaginal fascia (VVF) and to determine its relationship to the anterior branches of the IHP. This dissection study examined the fascial layers between the posterior urinary bladder and anterior vagina/cervix (VVF) in 15 female embalmed cadavers and three fresh specimens. Anterior branches of the IHP were identified and followed distally. The relationship between these nerve projections and the VVF was examined. In 16 dissection, the VVF was identified as a complete fascial plane extending beneath the vesicouterine pouch to the neck of the bladder inferiorly and to the endopelvic fascia laterally. Anterior projections from the hypogastric nerves and IHP maintained an extraperitoneal course passing anteriorly to the VVF towards the urinary bladder The VVF is a distinct fascial structure and projections of the hypogastric nerves pass anterior to this. This may have implications for nerve sparing hysterectomy.

886 Healing Hands and Thrifty Plans! A Prospective, Cost-Effective Trial in Abscess Management

Aim

Cutaneous abscesses are ubiquitous presentations requiring surgical drainage in most cases. There is a wide variation across the UK in the surgical practice dealing with such common problem. The aim of this study was to reduce the costs incurred in surgical drainage of acute skin and soft tissue abscess.

Method

This was a prospective, cost-effective study of the expenses incurred in surgical drainage of acute cutaneous and subcutaneous abscesses treated under the general surgeons' care over one year.

Results

A consequential saving of £13,962 was achieved during the study period. Between October 2019 and October 2020, 322 patients with soft tissue abscesses were treated by incision and drainage in general surgery. We calculated a total cost of £55.26 per patient for this routine operation. These expenses were based on basic surgical drapes pack, standard surgical gowns, sterile gloves and obtaining and processing the microbiology specimens. We have designed and implemented a new theatre protocol specifically for this procedure, resulting in a substantial reduction of the costs to £11.90 per patient. The total savings of £13,962 do not include savings caused by abscess drainage under local anaesthesia and does not calculate the savings that occurred due to shorter inpatient stay. These extra savings will be calculated and added later.

Conclusions

Considering the increasing financial burden on the NHS, we could make significant savings of nearly 80% of the operative costs of surgical drainage of a cutaneous abscess. We could achieve that by implementing simple modifications in the current surgical pathways without compromising patients' safety.

417 Initial Choice of Imaging Investigation for Patients Presenting with Acute Pancreatitis: Should MRCP Be First Line in Selected Patients?

Introduction

Current guidelines for acute pancreatitis advocate abdominal ultrasound (AUS) as the first-line imaging investigation to identify if gallstones are the cause of pancreatitis. However, many patients have a history of cholecystectomy or present with known gallstones and deranged liver function tests (LFTs). In these patients, magnetic resonance cholangiopancreatography (MRCP) is indicated due to its higher sensitivity and specificity for detecting choledocholithiasis.

Method

This retrospective audit reviewed all consecutive patients who presented to the surgical assessment unit with acute pancreatitis over one month. Their past surgical history, bloods and imaging were reviewed.

Results

Of the 30 patients, seventeen (57%) had no previous cholecystectomy or known gallstones, nine (30%) had previous cholecystectomy and eight (27%) had known gallstones, seven (88%) of which presented with deranged LFTs. Of the seventeen patients who should have had AUS first (n = 17), thirteen (76%) had AUS first, none had MRCP first and four (24%) had computerised tomography (CT) first. Of the patients in whom MRCP was indicated first-line (n = 13), seven (54%) had AUS first, none had MRCP first, four (31%) had CT first and two (15%) went straight to endoscopic retrograde cholangiopancreatography having had recent outpatient MRCPs. In the seven patients in whom MRCP was indicated but AUS was performed first, six (86%) underwent subsequent MRCP.

Conclusions

MRCP should be considered the first line imaging investigation for patients presenting with acute pancreatitis and a history of cholecystectomy or known gallstones with deranged LFTs, as AUS rarely prevents the need for subsequent MRCP.

416 Hyperlipasaemia In an Adult Hospital Population: A Retrospective Audit Demonstrating A High Proportion of Non-Pancreatic Causes of a Diagnostically Raised Lipase

Introduction

Serum lipase is considered to be a more specific test than amylase for acute pancreatitis, and a rise of over three times the laboratory upper limit of normal (ULN) is considered diagnostic. This single-centre retrospective audit assessed the accuracy of a raised lipase in confirming acute pancreatitis.

Method

All patients with a raised lipase (>78 U/L) admitted over one month were reviewed. Patients whose lipase was measured >48 hours after admission were excluded. Cross-sectional imaging and discharge summaries were reviewed to determine the cause of hyperlipasaemia. Receiver Operator Characteristics (ROC) analysis was performed to determine the most accurate cut-off value for diagnosing acute pancreatitis.

Results

Ninety-nine patients were included. The most common causes of raised lipase (>78 U/L) were pancreatitis (37%), hepatobiliary (15%), gastroduodenal (8%) and renal (8%) disease. In patients with a lipase >234 U/L (3xULN, n = 46), the most common causes were pancreatitis (70%), drugs (9%), hepatobiliary (9%), gastroduodenal (4%) and renal (4%) disease. ROC analysis showed lipase to have an area under the curve (AUC) of 0.89 (95% CI 0.84-0.96, p < 0.0001). Using the laboratory cut-off of 234 U/L (3xULN), lipase had a sensitivity, specificity, and positive likelihood ratio (PLR) of 86.5%, 77.4% and 3.8. Increasing the lipase cut-off did not improve the specificity without compromising the sensitivity of the test.

Conclusions

A lipase cut-off of 3xULN is an appropriate cut-off for a biochemical diagnosis of acute pancreatitis. However, up to 30% of patients with lipase values above this cut-off may have alternative diagnoses that should be considered.

Intention to Treat Laparoscopic Versus Open Hemi-Hepatectomy: A Paired Case-Matched Comparison Study

BACKGROUND

The benefits of laparoscopic hemi-hepatectomy compared to open hemi-hepatectomy are not clear.

OBJECTIVE

This study aims to share our experience with the laparoscopic hemi-hepatectomy compared to an open approach.

METHODS

A total of 40 consecutive laparoscopically started hemi-hepatectomy (intention-to-treat analysis) cases between August 2012 and October 2015 were matched against open cases using the following criteria: laterality of surgery and pathology (essential criteria); American Society of Anesthesiologists score, body mass index, pre-operative bilirubin, neo-adjuvant chemotherapy, additional procedures, portal vein embolization, and presence of cirrhosis/fibrosis on histology (secondary criteria); age and gender (tertiary criteria). Hand-assisted and extended hemi-hepatectomy cases were excluded from the study. The two groups were compared for blood loss, operative time, hospital stay, morbidity, mortality, and oncological outcomes. All complications were quantified using the Clavien-Dindo classification.

RESULTS

Two groups were well matched (p = 1.00). In the two groups, 10 patients had left and 30 had right hemi-hepatectomy. Overall conversion rate was 15%. Median length of hospital and high dependency unit stay was less in the intention to treat laparoscopic hemi-hepatectomy group: 6 versus 8 days, p = 0.025 and 1 versus 2 days, p = 0.07. Median operative time was longer in the intention to treat laparoscopic hemi-hepatectomy group: 420 min (range: 389.5-480) versus 305 min (range: 238.8-348.8; p = 0.001). Intra-operative blood loss was equivalent, but the overall blood transfusions were higher in the intention to treat laparoscopic hemi-hepatectomy (50 vs 29 units, p = 0.36). The overall morbidity (18 vs 20 patients, p = 0.65), mortality (2.5%), and the positive resection margin status were similar (18% vs 21%, p = 0.76). The 1- (87.5% vs 92.5%, p = 0.71) and 3-year survival (70% vs 72.5%, p = 1.00) was also similar.

CONCLUSIONS

We observed lower hospital and high dependency unit stay in the laparoscopic group. However, the laparoscopic approach was associated with longer operating time and a non-significant increase in blood transfusion requirements. There was no difference in morbidity, mortality, re-admission rate, and oncological outcomes.

The pre-operative rate of growth of colorectal metastases in patients selected for liver resection does not influence post-operative disease-free survival

AIMS

To assess the potential association between the change in diameter of colorectal liver metastases between pre-operative imaging and liver resection and disease-free survival in patients who do not receive pre-operative liver-directed chemotherapy.

MATERIALS AND METHODS

Analysis of a prospectively maintained database of patients undergoing liver resection for colorectal liver metastases between 2005 and 2012 was undertaken. Change in tumour size was assessed by comparing the maximum tumour diameter at radiological diagnosis determined by imaging and the maximum tumour diameter measured at examination of the resected specimen in 157 patients.

RESULTS

The median interval from first scan to surgery was 99 days and the median increase in tumour diameter in this interval was 38%, equivalent to a tumour doubling time (DT) of 47 days. Tumour DT prior to liver resection was longer in patients with T1 primary tumours (119 days) than T2-4 tumours (44 days) and shorter in patients undergoing repeat surgery for intra-hepatic recurrence (33 days) than before primary resection (49 days). The median disease-free survival of the whole cohort was 1.57 years (0.2-7.3) and multivariate analysis revealed no association between tumour DT prior to surgery and disease-free survival.

CONCLUSIONS

The rate of growth of colorectal liver metastases prior to surgery should not be used as a prognostic factor when considering the role of resection.

Platelets: the few, the young, and the active

Many modern automated cell counters in high-volume clinical hematology laboratories use new, improved technologies for routine platelet analysis. The latest progress includes the use of state-of-the art information technology, specific fluorescent dyes, and monoclonal antibodies to obtain more reliable platelet counts. This information allows the accurate and precise enumeration of platelets even in thrombocytopenic patients and the reporting of novel platelet parameters. In the near future, digital image analysis may permit even better platelet analysis.

Performance evaluation of the Sysmex haematology XN modular system

Background

The Sysmex XN haematology instrument performs automatic reflex testing, depending on sample results. A nucleated red blood cell (NRBC) count is provided on all samples. The instrument has a smaller footprint (34%) than previous Sysmex XE analysers.

Methods

An evaluation comparing all results to the Sysmex XE-2100 and manual microscopic differential and morphology (n=390) was performed followed by a workflow study of 1000 samples to compare speed of operation and number of blood films reviews required from both systems.

Results

The new features on the instrument are: (1) white cell and NRBC channel, all samples include the NRBC count; (2) white cell precursor channel: false positive flags for blasts, abnormal lymphocytes and atypical lymphocytes are reduced significantly without a statistical increase of false negatives; (3) low white cell count mode: suggested setting of <0.5×109/l. An extended count is more precise and provides an accurate differential. Fluorescent platelet count is performed in a dedicated channel. If the red cell or platelet size histograms are abnormal or if the platelet count is low, then a fluorescent platelet count is automatically performed. Good correlation with the XE-2100 and manual differential was found and the improved results compared to the reference flow cytometric analysis for platelet counts, especially below 30×109/l (XE-2100, R2=0.500; XN, R2=0.875).

Conclusion

The XN showed reduced sample turnaround time of 10% and reduced number of blood films for examination, 49% less than the XE-2100 without loss of sensitivity with more precise and accurate results on low cell counts.

The accuracy of platelet counting in thrombocytopenic blood samples distributed by the UK National External Quality Assessment Scheme for General Haematology

A knowledge of the limitations of automated platelet counting is essential for the effective care of thrombocytopenic patients and management of platelet stocks for transfusion. For this study, 29 external quality assessment specimen pools with platelet counts between 5 and 64 × 10(9)/L were distributed to more than 1,100 users of 23 different hematology analyzer models. The same specimen pools were analyzed by the international reference method (IRM) for platelet counting at 3 reference centers. The IRM values were on average lower than the all-methods median values returned by the automated analyzers. The majority (~67%) of the automated analyzer results overestimated the platelet count compared with the IRM, with significant differences in 16.5% of cases. Performance differed between analyzer models. The observed differences may depend in part on the nature of the survey material and analyzer technology, but the findings have implications for the interpretation of platelet counts at levels of clinical decision making.

ICSH recommendations for identification, diagnostic value, and quantitation of schistocytes

Schistocytes are fragments of red blood cells (RBCs) produced by extrinsic mechanical damage within the circulation. The detection of schistocytes is an important morphological clue to the diagnosis of thrombotic microangiopathic anemia (TMA). Reporting criteria between different laboratories, however, are not uniform, owing to variability of shape and nature of fragments, as well as subjectivity and heterogeneity in their morphological assessment. Lack of standardization may lead to inconsistency or misdiagnosis, thereby affecting treatment and clinical outcome. The Schistocyte Working Group of the International Council for Standardization in Haematology (ICSH) has prepared specific recommendations to standardize schistocyte identification, enumeration, and reporting. They deal with the type of smear, method of counting, morphological description based on positive criteria (helmet cells, small, irregular triangular, or crescent-shaped cells, pointed projections, and lack of central pallor). A schistocyte count has a definite clinical value for the diagnosis of TMA in the absence of additional severe red cell shape abnormalities, with a confident threshold value of 1%. Automated counting of RBC fragments is also recommended by the ICSH Working Group as a useful complement to the microscope, according to the high predictive value of negative results, but worthy of further research and with limits in quantitation.

Age estimation and the developing third molar tooth: an analysis of an Australian population using computed tomography

The third molar tooth is one of the few anatomical sites available for age estimation of unknown age individuals in the late adolescent years. Computed tomography (CT) images were assessed in an Australian population aged from 15 to 25 years for development trends, particularly concerning age estimation at the child/adult transition point of 18 years. The CT images were also compared to conventional radiographs to assess the developmental scoring agreement between the two and it was found that agreement of Demirjian scores between the two imaging modalities was excellent. The relatively wide age ranges (mean ± 2SD) indicate that the third molar is not a precise tool for age estimation (age ranges of 3-8 years) but is, however, a useful tool for discriminating the adult/child transition age of 18 years. In the current study 100% of females and 96% of males with completed roots were over 18 years of age.

Relationship of reported clinical features of pre-eclampsia and postpartum haemorrhage to demographic and other variables

BACKGROUND

Maternal death and disability remain significant problems in developing countries and are predominantly caused by preeclampsia and postpartum haemorrhage. The diagnostic criteria for preeclampsia and postpartum haemorrhage require medical technologies not readily available in underdeveloped areas.

OBJECTIVE

To determine the correlates of pre-eclampsia and postpartum haemorrhage using symptoms in a rural setting.

METHODS

This was a cross-sectional study in which 577 women from the Kwahu South District of the Eastern Region of Ghana completed questionnaires that sought for signs and symptoms of pre-eclampsia and postpartum haemorrhage in their current or prior pregnancies. The study was conducted over a period of two months, symptoms of pre-eclampsia assessed included headache, visual disturbance, urination, breathing, leg swelling and seizures. For postpartum haemorrhage, the following features were assessed: placenta delivery, length of labour, difficult delivery of placenta, lacerations associated with delivery, size of newborn, headache, visual disturbance and amount of vaginal bleeding.

RESULTS

There was a significant association between education and the number of signs and symptoms of preeclampsia, (Χ² =9.059, =0.018; OR no education vs >7 years=6.8). Mothers with no education were about seven times more likely to have all six signs and symptoms of preeclampsia than those with seven or more years of education. There was no significant association between education and postpartum haemorrhage, (Χ² = 1.835, = 0.400). However, the OR of 1.59, indicated an inverse association between the two variables.

CONCLUSION

The high number of symptoms associated with preeclampsia among women with no formal education strongly supports the need for educational outreach and basic prenatal care in rural Ghana.

ICSH review of the measurement of the erythocyte sedimentation rate

In recognition of the need for a standardization of the measurement of the erythrocyte sedimentation rate (ESR), the International Council for Standardization in Haematology makes the following recommendations: (i) The reference method for measurement of the ESR should be based on the Westergren method, which is a specific test for the ESR, with modifications, (ii) The reference method for measurement of the ESR should use either whole blood anticoagulated with EDTA and later diluted with sodium citrate or saline (4 : 1) or whole blood anticoagulated with sodium citrate (4 : 1) in Westergren pipettes, (iii) The ESR pipettes can be of glass or plastic (with specific characteristics). It must be colourless; a minimum sedimentation scale of 200 mm, a minimum bore of 2.55 mm, which should be constant within 5%. A protocol for the evaluation of alternative methodologies against the reference method is outlined: The new technologies must be tested over a range of ESR values of 2-120 mm. In this comparison, 95% of the differences should be 5 mm or less, with larger differences associated with higher ESR values. A minimum of 40 samples should be tested in 3 different groups of values: 1-20, 21-60 and more than 60 mm. The statistical methods recommended for ESR evaluations are the coefficient of correlation, the Passing-Bablock regression and the Bland-Altman statistical method. This reference method replaces all earlier standardized and reference methods.

Analysis of time of closure of the spheno-occipital synchondrosis using computed tomography

Current knowledge concerning closure of the spheno-occipital synchondrosis is inadequate for age estimation purposes in that of the few detailed studies conducted, these demonstrate considerable variation concerning the age at which the synchondrosis commences and completes fusion, thus creating uncertainty for forensic investigators who may use this developmental feature for age determinations. The aim of the present study was to determine the sequence and timing of closure of the spheno-occipital synchondrosis for a large sample of a modern Australian population to assess if this age marker is a useful tool for age estimation for individuals around the age of 18 years. The sample consisted of 666 individuals in the age range 15-25 years, who were admitted to the Victorian Institute of Forensic Medicine (VIFM) mortuary and who had undergone routine full body multi-slice CT imaging. Results show that fusion was well underway by the age of 15 years and was complete by 17 years. Fusion begins superiorly and progresses inferiorly. Persistence of a scar at the site of fusion was demonstrated through to age 25 years. After the age of 16 years there was no significant difference in progress of fusion between males and females. The study showed that this age marker is of limited value for age estimations around the age of 18 years in this population.

Iliotibial band syndrome: an examination of the evidence behind a number of treatment options

Iliotibial band (ITB) syndrome (ITBS) is a common cause of distal lateral thigh pain in athletes. Treatment often focuses on stretching the ITB and treating local inflammation at the lateral femoral condyle (LFC). We examine the area's anatomical and biomechanical properties. Anatomical studies of the ITB of 20 embalmed cadavers. The strain generated in the ITB by three typical stretching maneuvers (Ober test; Hip flexion, adduction and external rotation, with added knee flexion and straight leg raise to 30 degrees ) was measured in five unembalmed cadavers using strain gauges. Displacement of the Tensae Fasciae Latae (TFL)/ITB junction was measured on 20 subjects during isometric hip abduction. The ITB was uniformly a lateral thickening of the circumferential fascia lata, firmly attached along the linea aspera (femur) from greater trochanter up to and including the LFC. The microstrain values [median (IQR)] for the OBER [15.4(5.1-23.3)me], HIP [21.1(15.6-44.6)me] and SLR [9.4(5.1-10.7)me] showed marked disparity in the optimal inter-limb stretching protocol. HIP stretch invoked significantly (Z=2.10, P=0.036) greater strain than the SLR. TFL/ITB junction displacement was 2.0+/-1.6 mm and mean ITB lengthening was <0.5% (effect size=0.04). Our results challenge the reasoning behind a number of accepted means of treating ITBS. Future research must focus on stretching and lengthening the muscular component of the ITB/TFL complex.

Quality counts: new parameters in blood cell counting

Recently several parameters have been introduced to the complete blood count such as nucleated red blood cells, immature granulocytes; immature reticulocyte fraction, immature platelet fraction and red cell fragments as well as new parameters for detection of functional iron deficiency. Leucocyte positional parameters, which may diagnose specific diseases (e.g. differentiate between abnormal lymphocytes in leukaemia and viral conditions and may also detect malarial infection) are now available. At this time they are only used for research; however, generally such parameters later become reportable. One manufacturer's routine analyser allows measurement of cells by flow cytometry using monoclonal antibodies. Currently, there are no accredited external quality assessment schemes (EQAS) for these parameters. For a number of parameters, on some instruments, there is no internal quality control, which brings into question whether these parameters should be used for clinical decision making. Other more established parameters, such as mean platelet volume, red cell distribution width and the erythrocyte sedimentation rate do not have EQAS available. The UK National EQAS for General Haematology held a workshop earlier this year in 2008 to discuss these parameters. Participants were asked to provide a consensus opinion on which parameters are the most important for inclusion in future haematology EQAS.

Measurement of CD4+ T cells in point-of-care settings with the Sysmex pocH-100i haematological analyser

The decision to provide antiretroviral therapy to HIV-positive patients mainly depends on the CD4(+) T-cell count, with therapy indicated at a cut-off value of <350-200 CD4(+) T cells/microl blood. Monitoring patients is still a major problem in countries with limited resources where blood samples often have to be transported over long distances to regional referral centres in which the count can be performed on flow cytometers. We have evaluated a newly developed simple and inexpensive method for CD4(+) T-cell quantification. It is a variation of the Invitrogen T4 Quant kit, with manual isolation of nuclei from CD4(+) T cells and subsequent counting on the small haematology analyser pocH-100i, Sysmex. We have demonstrated that this new method is highly reproducible and gives stable and linear results over a wide range of CD4(+) T-cell concentrations. Method comparison to two different flow cytometers showed excellent correlation with concordances of about 93%. Overall, this method is rapid, easy to perform and offers a good reliable alternative to measurement by flow cytometry. The pocH-100i has the additional benefit of providing a complete blood count with a three-part white blood cell differential and software for patient data storage and handling.

Continuing developments with the automated platelet count1

The four main procedures for platelet counting are: manual phase contrast microscopy, impedance, optical light scatter/fluorescence and flow cytometry. Early methods to enumerate platelets were inaccurate and irreproducible. The manual count is still recognized as the gold standard or reference method, and until very recently the calibration of platelet counts by the manufacturers of automated cell counters and quality control material was performed by this method. However, it is time-consuming and results in high levels of imprecision. The introduction of automated full blood counters using impedance technology resulted in a dramatic improvement in precision. However, impedance counts still have limitations as cell size analysis cannot discriminate platelets from other similar-sized particles. More recently, light scatter or fluorescence methods have been introduced for automated platelet counting, but there are still occasional cases where an accurate platelet count remains a challenge. Thus, there has been interest in the development of an improved reference procedure to enable optimization of automated platelet counting. This method utilizes monoclonal antibodies to platelet cell surface antigens conjugated to a suitable fluorophore. This permits the possible implementation of a new reference method to calibrate cell counters, assign values to calibrators, and to obtain a direct platelet count on a variety of pathological samples. In future, analysers may introduce additional platelet parameters; a reliable method to quantify immature or reticulated platelets would be useful.

Development of an automated malaria discriminant factor using VCS technology

Malaria diagnosis presents a challenge to all laboratories. There is a need for rapid, sensitive, and cost-effective screening on all samples, particularly in areas where malaria is endemic. Response to malaria infection involves an increased monocyte count and production of large activated monocytes. These changes can be detected by volume, conductivity, and scatter (VCS) technology on certain automated blood cell counters (Beckman Coulter, Miami, FL). The SD of the volume of lymphocytes and monocytes demonstrates a significant difference from normal when malaria is present. By using a calculation derived from the SD volume of the lymphocytes and monocytes, herein termed the malaria factor, sensitivity of 98% and specificity 94% were demonstrated for the detection of malaria. Based on this derived discriminant, VCS technology should become a useful tool in the detection of malaria. A flag to indicate the potential presence of malaria could then be generated by the instrument if the user or manufacturer chose to do so.