Article Text

Download PDFPDF
Letter to the Editor
A prospective pilot survey of the impact of general practitioner generated full blood count requests on clinical haematology workload: a London teaching hospital experience
  1. M S Islam,
  2. B Sharma,
  3. K Sullivan,
  4. B J Hunt
  1. Department of Haematology, Guy's & St Thomas' Hospital, London, UK
  1. Correspondence to Professor B J Hunt, Department of Haematology, Guy's & St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK; beverley.hunt{at}

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Workload measurement is critical for planning, programming and staffing an organisation.1 Rising consumer expectation, the growing and ageing population and the increases in the number and technical sophistication of medical interventions have increased the workload in haematology laboratories as in other laboratory specialities,2 3 both from primary and secondary care. Since 1996, the National Pathology Benchmarking Study has conducted annual cycles of comparative analysis of the workload and organisation of haematology departments in the UK.4 In the current economic climate and with the trend towards laboratory centralisation, many laboratories are moving the analysis of general practitioner (GP)-requested samples to central laboratories. However, there are no studies that specifically aimed to determine the laboratory workload generated by the GP requests and the clinical haematology workload specifically emanating from GP-requested samples. Full blood count (FBC) analysis is a commonly requested laboratory investigation by all types of healthcare professionals in both primary and secondary care. We aimed to determine the magnitude of the laboratory and clinical haematological workload generated by GP-requested FBC samples by conducting a prospective pilot survey in our inner city haematology laboratory. To our knowledge, no previous studies have specifically determined the clinical haematology laboratory workload from FBC request by GPs.

This survey was conducted in the Laboratory Haematology section of GSTS, which serves Guy's and St Thomas' Trust (GSTT) and 131 local GP practices. The latter covers an estimated population of 550 000 in the London Boroughs of Lambeth and Southwark. This is a multiethnic population with a high turnover of patients and has the highest prevalence of sickle cell disease in Western Europe. Approval was obtained from the GSTT clinical audit department to conduct this survey. Information on the FBC samples submitted by 131 GP practices to our haematology laboratory for 23 consecutive days (excluding Sundays) was collected. The total number of FBC samples from all sources was used for comparison.

A structured pro forma was used to collect the information on patients' demographic details, calls made by biomedical scientists (BMSs) and duty haematologists to the GPs as a result of abnormal FBCs and the outcome of those calls (table 1), number of blood films made and examined by the BMS and/or haematologist, those referred to either haematology outpatients or the emergency department, and lastly information on malarial parasite (MP) identification requests.

Table 1

Telephone calls to GP by duty haematologist

Blood samples were collected using standard EDTA anticoagulated vacuum tubes, then couriered to the St Thomas' haematology laboratory and analysed on a Beckman Coulter analyser within 6 h of receipt. Blood films were made according to the ‘in-house’ standard operating procedure (table 2) which was validated against the International Consensus Group for Haematology Review guideline.5

Table 2

Criteria used as indication for preparing a blood film

BMSs referred the blood film to duty clinical haematologists according to the local policy (table 3).

Table 3

Criteria for blood film referral to duty clinical haematologist

Critical results were communicated to the GPs initially by the BMS. Subsequently the duty haematologist would discuss critical results with the referring GP. Non-critical abnormal results were usually communicated to the GPs by the BMS unless the results were new or worsening in which case the duty haematologist would contact the GPs for further information and evaluation.

Initial malaria screening was performed by the Quantitative Buffy Coat method using the Becton-Dickinson Malaria Diagnosis Kit. If the Quantitative Buffy Coat was positive, testing was performed to identify the Plasmodium species and to quantitate the infection, using the immunochromatographic test—a serological test using the BinaxNOW and microscopic examination of thick films (10% Giemsa stained) and thin films (methanol fixed and 10% Giemsa stained).

A total of 43 270 FBC samples were analysed over the survey period of which 8242 (19.04%) samples were requested by GPs. There was up to 6% day-to-day variation of GP workload except on Saturdays when the GP workload was about 10–12% less than on weekdays (figure 1), as GP practices were either closed or open for a limited time on Saturdays. No GP-requested FBC samples were received on Sundays.

Figure 1

Distribution of general practitioner-requested full blood count (FBC) samples.

A total of 445 (5.4%) blood films from GP-requested samples were made and all blood films were reviewed. Only 23 (0.28% of total GP-requested FBC samples and 5.1% of GP-requested blood films) blood films were referred to a duty clinical haematologist. Twenty-four (0.29% of total GP requests) samples had a specific request to investigate MP and of these four (0.05% of total GP-requested samples and 16.7% of the MP requests) were positive; Plasmodium falciparum and Plasmodium ovale were detected equally.

BMSs and duty haematologists telephoned GPs 21 times (0.25% of GP-requested samples) and 15 times (0.18% of GP-requested samples), respectively. We did not collect data on the amount of time and resources required to communicate with GPs; however, it was noted that it was often time-consuming to contact GPs directly because they were either with their patients or the practice protocol barred the reception staff from transferring the calls to GPs. Seven (50%) of the calls made by duty haematologists resulted in non-urgent referral of the patients to haematology outpatient departments and two (14.2%) calls resulted in urgent referral to the emergency department. Of the calls made to GPs, 21 (58.3%) out of a total of 36 were made out of hours as the majority of GP samples arrived in the late afternoon. These out-of-hours calls were rather more difficult for two reasons: first, as many practices were closed by the time calls were made, hence the communication was made through ‘NHS Direct’—an out-of-hours GP service, a time-consuming process; second, the on-call GPs were usually not familiar with the patient.

In summary, our survey has shown that GP-generated FBC requests accounted for a fifth of the total FBC requests to our haematology laboratory. Blood films were made and reviewed for 5.4% of GP-requested samples, which is a small percentage of film preparation compared with another study based on samples from both GPs and the hospital where 25% of patients had films made but only 16% were examined.6 Another published study showed a wide range of prepared blood films being unreported (0.14–71%).4 Our survey showed that as expected the percentage of GP-requested FBC samples that required blood film review was significantly smaller than that of the hospital patients, reflecting a lower rate of significant morbidity.

The limitations of this survey were that it was performed in a single institution and during a short time period in the summer. Accurate and useful data concerning the GP workload on haematology laboratory is difficult to collect for multiple laboratories serving overlapping populations. Larger, multicentre prospective studies throughout the year are required to validate our findings.

In conclusion, we have shown that the workload generated by the GP-requested FBC samples in our laboratory was considerable, but less than 1% of those required non-urgent clinical haematology evaluation and an even smaller percentage required urgent clinical management.

Take-home messages

  • In our inner city teaching hospital, one-fifth of the laboratory haematology workload was generated by general practice.

  • However <1% of general practitioner-requested samples resulted in referrals to clinical haematology either electively or as an emergency.

  • Only about 5% of general practitioner-requested full blood count samples required blood film examination.

  • This information may be helpful in workforce planning for clinical haematology.


We wish to thank the staff of Clinical and Laboratory Haematology at Guy's & St Thomas' and GSTS for their help in collecting the data.



  • Competing interests None.

  • Ethics approval This study was approved by the Guy's and St Thomas' Trust clinical audit department.

  • Provenance and peer review Not commissioned; externally peer reviewed.