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Publication - Guidance

Demand optimisation in diagnostics: standardising diagnostic testing in NHS Boards

Published: 22 Feb 2017
Part of:
Health and social care
ISBN:
9781786528032

Report highlighting current good practice, guidance on strategy and support for implementing demand optimisation.

69 page PDF

1.4MB

69 page PDF

1.4MB

Contents
Demand optimisation in diagnostics: standardising diagnostic testing in NHS Boards
Appendix D - Minimum Retesting Intervals Focus

69 page PDF

1.4MB

Appendix D - Minimum Retesting Intervals Focus

Background

Unnecessary repeat testing represents wastage within scarce healthcare budgets. The concept of defining, where possible, time intervals whereby repeat testing would be unjustified, is one that could be useful for demand optimisation purposes. The Royal College of Pathologists have recently published guidance on Minimum Retesting Intervals in Pathology 1 (2015). This guidance serves as a baseline for laboratory services to define, in conjunction with their users, a strategy for limiting unnecessary repeat testing within their domain.

While some requesting interval blocking can be made at the laboratory/radiology department level, the most appropriate focus for improvement work would be the point of request, usually the clinical user's requesting interface - such as the order communications module - to ensure unnecessary test requests can be avoided before an order is made or a specimen taken. The early adoption of automated IT systems, as they are developed, should be encouraged. The actual mode of interaction will depend on the test in question, especially with regards to the volume of samples being received, the cost of the test and the clinical risks involved in actually blocking requests.

The National Demand Optimisation Group has recommended a workstream to explore and agree national minimum retesting intervals. The following information represents areas of key focus for each discipline, demonstrating existing variation in some cases. Note that some of these MRIs represent pragmatic compromises to ensure that important though rare indications for more frequent testing are not inadvertently blocked:

1. Clinical Biochemistry - MRI Times

Test NHS Grampian NHS Fife Comments

Vitamin D

1 Year *

**

* only extremely rarely, a more
frequent service may be required

** Not available routinely in primary care. Only available when requested by key locations/consultants Any other circumstances contact duty clinical biochemist. Developing guidance

HbA1c

1 week *

60 Days

* MRI can be extended if diagnostic and monitoring based testing can be distinguished - if so then the
latter MRI could be 1 month

Cholesterol

1 month

All lipids MRI
60 days

Thyroid Function Test

1 week *

28 days

* MRI could be extended much further if clinical reason for request could be effectively interrogated via the order comms interface

CRP

20 hours *

48 hours

* Essentially a one day MRI in practice. Note some boards have implemented
a 3 day MRI.

Liver Function Test

20 hours *

No MRI for LFT's

* Essentially a one day MRI in practice

Transferrin

28 days

2. Haematology - MRI Times

Test NHS Grampian NHS Fife Comments

FBC

20 hours *

* Essentially a one day MRI in practice

INR

20 hours *

* Essentially a one day MRI in practice

3. Immunology - MRI Times

In NHS Tayside, all requests that fall inside the minimum retest interval are electronically held on LIMS system and scrutinised by a senior member of staff (Band 7 and above) before rejection or acceptance. This protocol allows clinical context to inform decision.

Test

Current Retest interval

Comments

Anti- TPO Abs

12 months

Repeats not routinely required

Anti- TRAB

12 months

Dependant on clinical context

Anti Gastric Parietal antibodies

Intrinsic Factor antibodies

12 months

Repeats not routinely required

Anti-adrenal antibodies

12 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

Anti-Smooth muscle antibodies

Anti-mitochondrial antibodies

Anti-M2 antibodies

Anti Liver Kidney Microsome antibodies

6 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

Anti-Neuronal antibodies

12 months

Repeats not routinely required

Anti glomerular basement membrane antibodies

4 weeks

Case by case basis for patients on therapy

Circulating skin antibodies

6 months

With discretion for patient on therapy for bullous pemphigoid

Anti tissue transglutaminase antibodies

6 months

frequency to be determined by clinical context

IgG endomysial

None

Only measured in patients with IgA deficiency

Anti nuclear antibodies ( ANA)

6 months

6 months

Anti-neutrophil cytoplasmic antibodies ( ANCA)

4 weeks

Case by case basis for patients on therapy

MPO/ PR3

42 days

Case by case basis for patients on therapy

Anti ds DNA antibodies

3 months

Case by case basis for patients on therapy

Anti-Extractable nuclear

antigens ( ENA)

12 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

Anti-cardiolipin antibodies

9 weeks

9-12 weeks retest to confirm positive results

Previously negative determined by clinical context

IgM Rheumatoid factor

12 months

Not routinely required-frequency to be determined by clinical context

Anti- cyclic citrillullated peptide antibodies ( CCP)

12 months

Not routinely required-frequency to be determined by clinical context

Complement C3 and C4

4 weeks

frequency to be determined by clinical context

lymphocyte subsets

1 week

All repeats must be discussed with consultant

Functional antibodies

2 years

Repeats to assess response to immunisation at 6-8 weeks on patients with previous levels below protective range.

Total IgE

6 months

For ABPA to assess efficacy of therapy

Allergen specific IgE

6 months

For ABPA to assess efficacy of therapy

IgG precipitins

6 months

For ABPA to assess efficacy of therapy

NMO Ab

12 months

Repeat testing guided by clinical context and only allowed if Oxford clinical questionnaire is completed

Basal ganglia Ab

24 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

C3 nephritic factor

12 months

Not routinely required if positive, only allowed if C3 below normal range

GAD

12 months

Not routinely required

Ganglioside Ab

12 months

Not routinely required

Histone Ab

12 months

Not routinely required

IA2 Ab

12 months

Not routinely required

IgG subclasses

12 months

Not routinely required

IgG4 - Repeat testing of limited clinical value -frequency to be determined by clinical context

Mast cell tryptase

28 days

frequency to be determined by clinical context re anaphylaxis versus mastocytosis monitoring

MAG Ab

12 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

Myositis panel

12 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

NMDA

3 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

Ovarian Ab

12 months

Not routinely required

Parathyroid antibodies

12 months

Not routinely required

Voltage gated KC and CC Ab

6 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

Anti-acetyl choline receptor antibodies

12 months

Frequency determined by clinical context - every 6 months on treatment

Anti- MUSK antibodies

12 months

Repeat testing of limited clinical value -frequency to be determined by clinical context

C1 inhibitor protein and activity

no limit

Once only to confirm, generally only performed if C4 is low or with compatible clinical information

NHS Grampian information-

ANA/ CTD Screen / ENA Screen

6 months

Liver Autoantibodies

6 months

IgA anti- TTG antibodies

12 months

Thyroid peroxidase antibodies

12 months

4. Microbiology/Virology - MRI Times

In general minimum tests intervals have not been implemented for Microbiology and Virology. The RCPATH guidelines for Minimum Retesting are based on expert opinion and as they are not being widely used there is an opportunity to formally validate them before being implemented.

There are some tests where there is established guidance on when to repeat the tests and labs do police the guidelines. These tests are a tiny percentage of the workload e.g. Viral load testing in HIV and retesting patients who are known to be positive for clostridium difficile.

There are large volume tests where MRI would be useful to reduce duplicate samples. Urine culture is an example. This topic needs to be discussed by the SMVN.

Test

Current Retest interval

Comments

Viral load testing in HIV

Depends on indication see BHIVA guidelines

http://www.bhiva.org/documents/Guidelines/Monitoring/2016-BHIVA-Monitoring-Guidelines.pdf

A small numbers expensive test where it is worthwhile enforcing guidelines

Clostridium Difficile testing

Some labs will not test a sample if there has been a previous positive in the last 10 days

NHS Grampian information-

ASO Tite

14 days

Helicobacter pylori serology

28 days if previously negative

Never repeat if previously positive

MRSA Screen

7 days

Urine microscopy and culture

3 days

5. Radiology - MRI Times

In imaging there is very little in the way of minimum retesting intervals. Repeat radiological investigations would be subject to IRMER regulations. Imaging benefits from global work lists, so investigations performed in other boards would be visible to all NHS Scotland staff so duplicate tests should not be performed unless clinically necessary and within guidelines.

The only exception highlighted to the NDOG is chest X-ray for improvement of appearances of infection for which the patient has been prescribed antibiotics. There is little point in re x-raying in less than 7 days as the antibiotic course will not have been completed. However the patient may need to have further chest X-Ray if the clinical condition worsens so a degree of clinical judgement will need to be applied in some cases.


Contact

Email: Karen Stewart