Appendix 1: Detailed break-down of test costs according to micro-costing
1. Cell culture cytotoxin neutralization assay (CCNA)
List price
(£)
Pack size
Unit cost
(£)
Resource
use per
test
Cost per
test (£)
Universal container (Sterilin)
57.99
400
0.14
1.00
0.14
Phosphate buffered saline
81.00
1000 ml
0.08
10.00 ml
0.81
Micro plate (confluent layer of Vero
cells in maintenance medium
containing HEPES) incl. lid
58.00
50
1.16
0.02
0.02
20 µl Clostridium sordelli antitoxin
60.00
500000 µl
0.0001
20.00 µl
0.0024
Pipette or swab
4.40
500
0.01
1.00
0.01
Pipette tip (20 µl)
31.79
2000
0.02
2.00
0.03
Tissue culture flasks (75 cm2)
211.41
100
2.11
0.01
0.01
Other reagents
0.50
1
0.50
1.00
0.50
Foetal bovine serum
30.00
500
0.06
0.30
0.02
Tissue culture media (HEPES)
17.40
1000
0.02
0.30
0.01
Gloves
4.87
100
0.05
0.25
0.01
Resource
Comment
Source
Consumables and reagents:
one flask for 4 plates
(152 samples), 2
wells per sample
includes continuous
line of cells and its
maintenance and
positive control
one flask (30 ml)
makes 4 plates (152
samples)
one flask (30 ml)
makes 4 plates (152
samples)
glove change every 4
samples assumed
http://www.sterilin.co.uk
(September 2011)
Purchasing Singelton
Hospital, Swansea, UK
Purchasing Singleton
Hospital, Swansea, UK
http://www.sterilin.co.uk
(September 2011)
http://www.sterilin.co.uk
(September 2011)
Head of laboratory and
purchasing Singleton
Hospital, Swansea, UK
Purchasing Singleton
Hospital, Swansea, UK
http://www.sigmaaldrich.com
(September 2011)
Purchasing Singleton
Hospital, Swansea, UK
£1.57
Total (consumables and reagents):
Material waste
made onsite, readymade price used
96 wells, 2 per test
needed + positive and
negative controls
5 ml bottle, diluted
1:100, 20 µl/test
http://www.sterilin.co.uk
(September 2011)
http://www.sigmaaldrich.com
(September 2011)
0.08 (5% of
total
consumable
0.0023
0.0002
on average 34
samples received per
day, materials for 38
Head of Virology, laboratory
staff
cost)
prepared, 5% wasted
Capital and overheads:
Overheads
2.00
Estimate (includes
space needed, cell
culture, lighting,
electricity, cleaning,
maintenance)
5 year lifespan
assumed, 10,000
samples a year,
assumption made that
only used for CCNA
Estimate
Purchasing Singleton
Hospital, Swansea, UK
Hospital statistics
Centrifuge (Sorval Legend RT)
6804.00
50000
0.14
1.00
0.14
Maintenance contract Centrifuge
210.00
10000
0.02
1.00
0.02
£ 210 per year
Purchasing Singleton
Hospital, Swansea, UK
Purchasing Singleton
Hospital, Swansea, UK
Hospital statistics
Purchasing Singleton
Hospital, Swansea, UK
Class 1 microbiological safety
cabinet (Leec)
10000.00
50000
0.20
1.00
0.20
5 year lifespan
assumed, 10,000
samples a year,
assumption made that
only used for CCNA
Maintenance contract safety cabinet
72.00
10000
0.01
1.00
0.01
£ 72 per year
5 year lifespan
assumed, 10,000
samples a year,
assumption made that
only used for CCNA
5 year lifespan
assumed, 10,000
samples a year,
assumption made that
only used for CCNA
Purchasing Singleton
Hospital, Swansea, UK
Hospital statistics
Vortex (Whirlimixer)
500.00
50000
0.01
1.00
0.01
Incubator (Leec Research CO2)
5000.00
50000
0.10
1.00
0.10
Maintenance contract microscope
54.00
10000
0.01
1.00
0.01
£ 54 per year
Purchasing Singleton
Hospital, Swansea, UK
0.10
5 year lifespan
assumed, 10,000
samples a year,
assumption made that
only used for CCNA
Purchasing Singleton
Hospital, Swansea, UK
Hospital statistics
Band 2 (£ 15,194)
Laboratory staff and
Microscope
5000.00
50000
0.10
1.00
Purchasing Singleton
Hospital, Swansea, UK
Hospital statistics
£2.58
Total (overhead and capital):
Staff costs:
Sample labelling
7.69/hour
60 mins
0.13/min
2.00 mins
0.26
Sample preparation
7.69/hour
60 mins
0.13/min
4.50 mins
0.58
Tidying up
7.69/hour
60 mins
0.13/min
0.50 mins
0.06
Cataloguing
7.69/hour
60 mins
0.13/min
0.50 mins
0.06
Sample reading (18 hours)
14.91/hour
60 mins
0.25/min
5.00 mins
1.24
Sample reading (48 hours)
14.91/hour
60 mins
0.25/min
5.00 mins
1.24
Reporting of results
14.91/hour
60 mins
0.25/min
2.00 mins
0.50
Staff training (preparation, trainee
time)
7.69/hour
60 mins
0.13/min
0.19
0.02
Staff training (preparation, trainer
time)
14.91/hour
60 mins
0.25/min
0.19
0.05
Staff training (reading, trainee time)
14.91/hour
60 mins
0.25/min
0.19
0.05
Staff training (reading, trainer time)
14.91/hour
60 mins
0.25/min
0.19
0.05
20.27
mins
£ 4.11
Total (staff):
Repeat samples
Total cost/test CCNA:
9.00
(approx.
test cost)
0.06
0.51
£8.78
Band 2 (£ 15,194), 45
mins for 10 samples
Band 2 (£ 15,194), 5
mins for 10 samples
Band 2 (£ 15,194), 5
mins for 10 samples
Band 6 (£ 29,464), 30
mins for 6 samples
Band 6 (£ 29,464), 30
mins for 6 samples
Band 6 (£ 29,464), 30
mins for 6 samples
Band 2 (£ 15,194),
assumed 4 days a
year = 32 hours =
1920 minutes per
10,000 samples
Band 6 (£ 29,464),
assumed 4 days a
year = 32 hours =
1920 minutes per
10,000samples
Band 6 (£ 29,464),
assumed 4 days a
year = 32 hours =
1920 minutes per
10,000samples
Band 6 (£ 29,464),
assumed 4 days a
year = 32 hours =
1920 minutes per
10,000samples
59/1034 samples
positive PCR but
negative CCNA;
would be sent again =
5.7 % of samples
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Clinical study data [17]
2. Xpert C. difficile rtPCR
List price
(£)
Pack size
Unit cost
(£)
Resource
use/test
Cost per
test (£)
PCR kit (incl. cartridge and reagents)
333.50
10
33.35
1.00
33.35
Sterile swab
14.91
100
0.15
1.00
0.15
Gloves
4.87
100
0.05
0.13
0.01
Resource
Comment
Source
Glove change every 8
samples assumed
Cepheid (no discount
applied)
http://www.sterilin.co.uk
(September 2011)
Purchasing Singleton
Hospital, Swansea, UK
one repeat sample
per 31 samples
Clinical trial data (33 repeats
in 1051 samples) [17]
Consumables and reagents:
£33.51
Total (consumables and reagents):
Material waste
33.51
0.03
1.08
Capital and overheads:
Overheads
0.02
Cepheid GeneXpert PCR (16-8)
63600.00
100000
0.64
1.00
0.64
Maintenance contract (16-8)
18221.00
50000
0.36
1.00
0.36
adjusted according to
space taken up in
comparison to CCNA
10 year life span =
124000 samples
(mean 10,000 per
year)
5 year warranty =
62000 samples
(mean 10,000 per
year)
Estimate
Cepheid and ABMUHB
statistics (assumption as
machine only on market
since 2006
Cepheid and ABMUHB
statistics
£1.02
Total (overhead and capital):
Staff costs:
Sample labelling
7.69/hour
60 mins
0.13/min
1.00 min
0.13
Sample preparation and test start
7.69/hour
60 mins
0.13/min
1.50 mims
0.19
Tidying up and entry on Masterlab
7.69/hour
60 mins
0.13/min
0.60 mins
0.08
Staff training (preparation, trainee
time)
7.69/hour
60 mins
0.13/min
0.01 mins
0.001
Band 2 (£ 15,194), 1
mins per sample
Band 2 (£ 15,194),
1.5 mins per sample
Band 2 (£ 15,194),
0.6 mins per sample
Band 2 (£ 15,194),
assumed 0.2 days a
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
year = 1.6 hours =
96.0 minutes per
10,000 samples =
0.0096 mins per
sample
Band 6 (£ 29,464),
assumed 0.2 days a
year = 1.6 hours =
96.0 minutes per
10,000 samples =
0.0096 mins per
sample
Staff training (preparation, trainer
time)
14.91/hour
60 mins
0.25/min
0.01 mins
0.002
Results check
14.91/hour
60 mins
0.25/min
0.20 mins
0.05
Band 6 (£ 29,464)
Reporting of results
14.91/hour
60 mins
0.25/min
0.50 mins
0.12
Band 6 (£ 29,464)
3.82 mins
£ 0.57
Total (staff):
Total cost/test PCR:
£36.18
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Laboratory staff and
personnel department
Appendix 2: Calculation of potential cost savings of rtPCR compared to routine CCNA
Parameter
Value
Comment
Calculation
(1) Samples/year by routine
CCNA
10,769
Number of samples tested in
ABMUHB 2011
n/a
(2) Positive patients/year
(CCNA)
289
Number of positives (all
ages) in ABMUHB 2011
n/a
(2a) Percentage of positive
samples
0.0268
(3) Negative samples/year
10,480
Percentage of positive
samples in ABMUHB in 2011
Number of negative samples
per year
5,240
Assumption made that
negative CCNA tests will be
repeated once per patient2
94,502.67
Assumption made that
initially negative CCNA tests
need to be repeated once
per patient2
(5) Cost testing PCR (all
samples); £
200,040.21
Only half of negative
samples tested i.e. every
patient tested once2
(6) Incremental cost PCR; £
105,537.54
(3a) Negative patients/year
(4) Cost testing CCNA (all
samples); £
(7) Positives earlier discharge;
days
(8) Negatives earlier
discharge; days
4.88
7.03
(9) Bed days saved positives
1,410.32
(10) Bed days saved
negatives
36,837.20
Mean study result PCRCCNA
Mean study result PCRCCNA
Mean bed days saved in
2011 for all positive patients
by using PCR instead of
CCNA
Mean bed days saved in
2011 for all negative patients
by using PCR instead of
CCNA; assumed all patients
Source
ABMUHB laboratory
statistics
Mandatory Surveillance
Report, Public Health
Wales for 20111
Positives(2)/Samples(1)
Samples(1) –
positives(2)
Hospital statistics
suggest high rate of
repeat samples for
CCNA
Cost/test CCNA [£8.78]*
samples(1)
(Cost/test PCR [£36.18]*
positives(1))+(Cost/test
PCR [£36.18]*
negatives(3a))
Cost PCR(5) - cost
CCNA(4)
ABMUHB laboratory
statistics and microcosting
ABMUHB laboratory
statistics and microcosting
Mean difference
according to study result
Mean difference
according to study result
Positives earlier
discharge(7)*positives(2)
Negatives earlier
discharge(8)*negative
patients(3a)
(11) Cost per bed day; £
334.17
(12) Cost savings/positive; £
1,630.75
(13) Cost savings/negative; £
2,349.22
(14) Savings all positives; £
470,649.34
(15) Savings all negatives; £
12,310,346.16
(16) Total savings; £
12,780,995.50
(17) Total net savings; £
12,675,457.96
(18) Cost savings per patient;
£
2292.62
tested twice with CCNA2
Weighted for speciality and
activity
Potential cost saving per
positive patient by using
PCR instead of CCNA
Potential cost saving per
negative patient by using
PCR instead of CCNA
Total potential cost savings
for all positive samples in
ABMUHB in 2011 if PCR is
used instead of CCNA
Total potential cost savings
for all negative samples in
ABMUHB in 2011 if PCR is
used instead of CCNA
NHS reference costs
20113
Positives earlier
discharge(7)*cost per
bed day(11)
Negatives earlier
discharge(8)*cost per
bed day(11)
Bed days saved
positive(9)*cost per bed
day(11)
Bed days saved
negative(10)*cost per
bed day(11)
Savings positive(14)
+savings negative(15)
Total potential net savings of
PCR compared to CCNA in
ABMUHB in 2011
Potential cost savings of
PCR compared to CCNA in
ABMUHB in 2011 per patient
Total savings(16) incremental cost PCR(6)
Net savings(17)/
(positives(2) + negative
patients(3a))
1 Welsh
Healthcare Associated Infection Programme. Clostridium difficile. Mandatory Surveillance Report. Abertawe Bro
Margannwg University Health Board. Public Health Wales. 2012: page 8 [19].
2For
the calculations it was assumed that negative CCNA samples would be repeated twice per patient while negative
PCR samples would only be done once. This assumption is based on a high rate of repeat samples for CCNA testing
according to ABMUHB laboratory statistics and recent literature suggesting a significant drop in repeat samples after
introduction of PCR [37]
3Department
of Health. NHS reference costs 2010-2011. Department of Health 2012, United Kingdom [18].