Preoperative blood tests: an expensive tick box exercise.
Abstract: The purpose of preoperative investigations is to provide diagnostic and prognostic information. Preoperative tests requested for a cohort of patients admitted for simple trauma related procedures were retrospectively reviewed. Adherence to the NICE guidelines was found to be 5%. No result from a blood test led to a change in the management of the patient. The authors believe that implementation of the NICE guidelines will reduce clinical time and result in huge financial savings for individual institutions.

KEYWORDS Preoperative blood tests / Routine / Costs / Benefits
Article Type: Report
Subject: Fractures (Diagnosis)
Fractures (Care and treatment)
Fractures (Research)
Blood (Medical examination)
Blood (Usage)
Authors: Pastides, Philip
Tokarczyk, Szymon
Ismail, Laura
Ahearne, David
Sarraf, Khaled
Pub Date: 12/01/2011
Publication: Name: Journal of Perioperative Practice Publisher: Association for Perioperative Practice Audience: Academic Format: Magazine/Journal Subject: Health; Health care industry Copyright: COPYRIGHT 2011 Association for Perioperative Practice ISSN: 1750-4589
Issue: Date: Dec, 2011 Source Volume: 21 Source Issue: 12
Topic: Event Code: 310 Science & research
Product: Product Code: 8000428 Blood Test Procedures NAICS Code: 6215 Medical and Diagnostic Laboratories
Geographic: Geographic Scope: United Kingdom Geographic Code: 4EUUK United Kingdom
Accession Number: 274700155
Full Text: Introduction

The purpose of preoperative investigations is to provide diagnostic and prognostic information prior to performing surgical procedures and anaesthetic interventions of an operation. This information can then be used to plan the surgical procedure and aid in predicting any potential complications. This is especially important for patients undergoing major operative procedures who have co-morbidities which may adversely affect the outcome.

The type of preoperative tests may range from simple investigations such as blood tests, electrocardiograms or radiographs to more complex ones such as computer tomographical studies or echocardiograms. With over seven million operations across all specialties funded by the NHS every year, the cost of all these investigations is considerable (HES 2001).

Background

The National Institute of Health and Clinical Excellence (NICE) has produced guidelines advising on the need for preoperative tests based on the complexity of the procedure to be undertaken, the patient's age and their American Society of Anesthesiologists (ASA) grade (NICE 2003a) The recommendations use traffic light colour coding: red (not recommended), yellow (consider) and green (recommended). These are freely available on the NICE website.

Methods

We retrospectively reviewed the preoperative tests requested for a cohort of patients admitted via our department for simple trauma related procedures over a two month period (November--December 2010). Using our hospital coding system, we searched for closed fractures of the leg that required operative fixation. Patient notes were retrospectively reviewed after the procedure, and the pre-admission drug history and co-morbidities were noted.

Our patient cohort was divided into two groups: aged below 40 (group A) and between 40 and 60 years old (group B). All patients under the age of 18 were excluded. Allowing for this exclusion, each group had 30 and 34 patients respectively.

The type of procedures this cohort underwent are shown in Table 1. They were deemed as intermediate procedures (grade 2) (NICE 2003b)

Results

None of the patients in group A had any significant co-morbidities, whilst eight patients in group B suffered with hypertension and one with hyperthyroidism.

None of the patients were taking any antiplatelet, anticoagulant or hypoglycaemic agents. No patients were known to suffer with diabetes (Table 2).

Biochemical requests

Ninety-five percent of patients had at least one blood test carried out. In total 296 tests were performed. All patients over the age of 40 had at least one blood test. These are shown in Figure 1.

Tests requested included full blood count (91%), urea and electrolytes (91%), coagulation screen (66%), liver function tests (67%), group and save (69%), creactive protein (CRP) (70%), erythrocyte sedimentation rate (ESR) (2%), thyroid function tests (5%) and creatinine kinase (CK) (2%).

None of the requested tests showed any significant abnormalities that altered either pre or postoperative management, or follow up.

[FIGURE 1 OMITTED]

Our study revealed a 5% adherence to the NICE guidelines, 3 patients in group A and 2 in group B.

The cost of individual tests varies from institution to institution. The range of costs for a single test (including staff time, laboratory and capital equipment cost) from several UK based institutes is shown in Table 3 (NICE 2003a).

Discussion

History and examination are an integral part in predicting the likelihood of complications related to surgery (Peterson et al 1992, Roshan & Rao 2000) Clinical investigations add further information about potential problems and allow planning for anticipated problems. This is especially important in complex surgical procedures involving patients who are at high risk or in the cases of emergency surgery.

However, the clinical value of testing healthy individuals before an operation is debatable (Garcia-Miguel et al 2003, Marcello & Roberts 1996). The possible benefits of routine preoperative investigations include identification of unsuspected conditions that may require treatment before surgery or a change in surgical or anaesthetic management. The American Society of Anaesthesiologists has stated that 'routine preoperative tests (i.e. tests intended to discover a disease or disorder in an asymptomatic patient) do not make an important contribution to the process of perioperative assessment and management of the patient by the anaesthesiologist' (Weinstein et al 1996).

The National Institute of Health and Clinical Excellence has laid out in an easy to read tabular format the recommendations on what tests, if any, are required, based on the complexity of the procedure and patient factors (NICE 2003a). The tables concerning our patient cohort (complexity of surgical intervention = intermediate) are shown in Figure 2.

Had these guidelines been followed, only the eight patients on anti-hypertensive medications could arguably have required preoperative biochemical investigations. Even if deemed ASA grade 2, then NICE recommends that full blood count and renal function screening should be 'considered'. This would have led to a dramatic 95% reduction (280/296) in the number of tests carried out.

A large systematic review (Munro et al 1997) investigating the value of routine preoperative testing in healthy or asymptomatic adults came to several important findings. The authors found that the tests produced a wide range of abnormal results even in apparently healthy individuals, and the clinical importance of these results was uncertain. Routine tests lead to changes in clinical management in only a very small proportion of patients (0.12.7%). They concluded that the power of preoperative tests to predict adverse postoperative outcomes in asymptomatic patients is either weak or non-existent. However, the same tests may have greater predictive power in defined high-risk populations.

In an audit similar to ours, Kaplan et al (1982) reviewed 773 routine investigations for patients awaiting surgery. Only 70 tests (9.1%) were abnormal. Management was altered in only two patients, both of which were diabetic patients. These findings have been supported by other studies (Johnson et al 1988, Smetana & Macpherson 2003).

Cost analysis

All tests have a cost associated with them. Even if the cost is relatively low per patient, the collective cost forms a significant part of an institution's budget.

Table 3 shows the range in costs for each of the common blood tests (NICE 2003b).

Table 4 shows the range in the amount spent on patients included in our cohort and hence the potential savings.

In our study we chose to use a common trauma case. Although not strictly an elective procedure, these are procedures that are generally not operated on the day of admission. It is important to stress that these represent guidelines and clinical judgement should always over rule implementation of recommendations.

All of the cases we have included were admitted via the accident and emergency department of our hospital and referred to the oncall junior doctor for admission. Some, if not all, of the blood tests would have been requested either by the treating accident and emergency doctor or by the admitting trauma doctor. The reason for these requests is not known, but it is fair to assume that they were done in view of a potential operative procedure. This may explain the request of full blood counts and coagulation screens. The request for thyroid function tests and inflammatory markers in the acute setting remain unjustifiable. Theoretical scenarios included a tick box exercise for grouping of bloods on accident and emergency request forms.

Amongst trainees, there is also a sense of concern that should appropriate 'screening' blood tests not be performed, then this may delay the patient going to theatre and result in cancellation or disruption to the list. This may lead to over-investigation of patients, to prevent such events from occurring.

At a time of economic cutbacks and need for savings, the unnecessary requesting of preoperative blood tests also has a financial burden upon the individual institutions.

We believe that implementation of the NICE guidelines will have several effects. Firstly, it will reduce unnecessary clinical time to analyse the samples. Secondly, it avoids the need for an uncomfortable venepuncture imposed upon the patient. Furthermore it will result in a huge financial saving for individual institutions. Our study looked at only a handful of procedures over a two month period from one surgical discipline. If this guideline was implemented across all surgical specialties then the financial gains could be very significant.

Another factor that needs to be considered is the incidental deranged test result and the potential need for further investigations to be performed to investigate the abnormal results. This obviously increases clinical time.

We recommend that institutions should recommend these guidelines following discussion and staff education between all relevant departments. Before requesting any test, the physician should ask themselves the following questions:

1) Will this investigation give me more information that I have not revealed in my physical examination?

2) Will the results of the investigation alter the management for this patient?

These guidelines should also form part of the induction process for all new junior trainees in accident and emergency, surgical and anaesthetic disciplines as these are the clinicians who are most likely to request the appropriate tests if required.

Conclusion

For all the tests reviewed, a policy of routine testing in apparently healthy individuals is likely to lead to little, if any, benefit. Munro et al (1997) concluded in their systematic review that testing would be of benefit in asymptomatic patients in defined groups, but there is not enough evidence to support or dismiss its routine use.

Our study also showed that some blood tests, such as inflammatory markers and thyroid function tests, were inappropriately requested.

This review has shown that adopting the NICE guidelines would have decreased the amount of unnecessary blood tests that patients undergo when they attend hospital for intermediate surgical procedures. This could possibly be extrapolated to routine and minor procedures as well, but further studies would be needed to confirm that. If these guidelines were implemented for all surgical procedures, this would undoubtedly result in a significant financial saving for the institution and the NHS as a whole. At our institution we have implemented surgical and anaesthetic team awareness and education around these guidelines in a bid to reduce the use of unnecessary testing.

References

Garcia-Miguel FG, Serrano-Aguilar PG, Lopez-Bastia J 2003 Preoperative assessment The Lancet 362 (9397) 1749-57

Hospital Episode Statistics Main procedures and interventions: summaiy Available from http://www.hesonline.nhs.uk/Ease/servlet/ContentSer ver?siteID=1937&categoryD=204 [Accessed October 2011]

Johnson H, Knee-Ioli S, Butler TA et al 1988 Are routine preoperative laboratory screening tests necessary to evaluate ambulatory surgical patients? Surgery 104 (4) 639-45

Kaplan EB, Boeckmann AS, Roizen MF, Sheiner LB 1982 Elimination of unnecessary preoperative laboratory tests Anesthesiology 57(Suppl 3) 445

Marcello PW, Roberts PL 1996 Routine preoperative studies: Which studies in which patients? Surgical Clinics North America 76 (1) 11-23

Munro J, Booth A, Nicholl J 1997 Routine preoperative testing: a systematic review Health Technology Assessment 1 (12) 1-62

National Institute for Health and Clinical Excellence 2003a Guidelines CG3 The use of routine preoperative tests for elective surgery London, NICE

National Institute for Health and Clinical Excellence 2003b Guidelines CG3 The use of routine preoperative tests for elective surgery: Appendices London, NICE

Peterson MC, Holbrook JH, Von Hales D, Smith LN, Staker LV 1992 Contributions of the history, physical examination and laboratory investigation in making medical diagnoses West Journal Medicine 156 (2) 163-5

Roshan M, Rao AP 2000 A study on relative contributions of the history, physical examination and investigations in making medical diagnosis Association Physicians India 48 (8) 771-5

Smetana GW, Macpherson DS 2003 The case against routine preoperative laboratory testing Medical Clinics North America 87 (1) 7-40

Weinstein MC, Siegel JE, Gold MR, Kamlet MS, Russell LB 1996 Recommendations of the panel on cost-effectiveness in health and medicine Journal of the American Medical Association 276 (15) 1253-8

Philip Pastides BSc (Hons), MBBS, MRCS, MAcadMEd

Post Core Orthopaedic Fellow, Whittington Hospital, London

Szymon Tokarczyk MBBS

SHO Trauma & Orthopaedics, Bassetlaw District General Hospital

Laura Ismail MBBS, BSc

Hillingdon Hospital--now at St Mary's Hospital, Imperial Healthcare Trust

David Ahearne MB ChB, FRCS (Tr & Orth)

Consultant Hand and Shoulder Surgeon, The Hillingdon Hospitals NHS Foundation Trust

Khaled M Sarraf BSc (Hons), MBBS, MRCS

Specialist Registrar (ST5) in Trauma and Orthopaedic Surgery, Chelsea and Westminster Hospital, London

No competing interests declared

Correspondence address: P Pastides, Department of Trauma and Orthopaedics, The Hillingdon Hospital, Pield Heath Road, Uxbridge, UB8 3NN. Email: ppastides@hotmail.com
Table 1 Breakdown of operative procedures in each group

Operative procedure                                       Group   Group
                                                            A       B

Open reduction and internal fixation of distal fibula      14      10
Open reduction and internal fixation of medial
  malleolus                                                 4       3
Open reduction and internal fixation of bimalleolar
  fracture                                                  7       8
Open reduction and internal fixation of trimalleolar
  fracture                                                  0       2
Tension band wiring patella fracture                        2       0
Open reduction and internal fixation of tibial plateau      3       8
Manipulation under anaesthesia for fracture                 0       3

Total                                                      30      34

Table 2 Co-morbidities in both groups

                   Group A    Group B

Hypertension          0          8
Hyperthyroidism       0          1
Diabetes              0          0

Table 3 Estimated unit cost range

                     Estimated unit cost
                   range ([pounds sterling])

                    Minimum      Maximum

Full blood count      0.70         4.05
Renal function        1.40         5.4
Coagulation           1.50         5.85

Source: National Institute for Health and Clinical

Excellence (2003a)

Figure 2 NICE recommendations for our patient cohort (NICE 2003a, b)

ASA Grade 1: adults = 16 years

                                   Age (years)

Test                 >16 to <40   >40 to <60   >60 to <80   >80

Chest x-ray              No           No           No        No
ECG                      No                                 Yes
Full blood count         No                       Yes       Yes
Haemostasis              No           No           No        No
Renal function           No           No
Random glucose           No
Urine analysis (a)

(a) Dipstick urine testing in asymptomatic individuals is not
recommended (UK National Screening Committee)

ASA Grade 2: adults with comorbidity
from cardiovascullar disease

                                    Age (years)

Test                 >16 to <40   >40 to <60   >60 to <80   >80

Chest x-ray
ECG                     Yes          Yes          Yes       Yes
Full blood count
Haemostasis              No           No           No        No
Renal function                                    Yes       Yes
Random glucose           No           No           No        No
Urine analysis
Blood gases              No           No           No        No
Lung function            No           No           No        No

Table 4 Estimated unit cost range of the blood
tests requested in our cohort

                       Estimated unit cost
                    range ([pounds sterling])

                     Minimum      Maximum

Full blood count      40.60        243.90
Renal function        81.20        313.20
Coagulation           63.00        245.70
Total                 184.80       802.80
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