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Technical Report
UTI Predictive Value—
Comparing the iQ 200 Series
to the Sysmex UF-1000i
®
®
Brian D. Miller
July 2009
UTI Predictive Value—
Comparing the iQ®200 Series to the Sysmex® UF-1000i
Technical Report
Brian Miller
The primary objective for this clinical assessment was to fully evaluate all aspects of
the UF1000i with regards to alignment with the iQ200 and its overall UTI screening
capabilities. Secondary objectives were the evaluation of the workflow and productivity of the UF-1000i, by way of throughput, turn around time and performance of
routine tasks. Additionally, the new Iris Diagnostics’ iChemVELOCITY urine chemistry system was utilized to obtain chemistry analytes in an effort to fully evaluate all
parameters for UTI screening available from Iris Diagnostics.
Purpose
The Iris Diagnostics iQ®200 Series of Automated Urine Microscopy Systems has
been shown to be an effective tool in screening for urinary tract infections (UTIs).
With the introduction of the Sysmex® UF-1000i Automated Urine Sediment Analyzer,
there is a need for a direct comparison between the two systems to determine if their
differing technologies give either system an advantage in screening for UTI.
Objectives
The primary objective for this clinical assessment was to fully compare the iQ200
Series with the UF-1000i with an emphasis on each system’s ability to screen for UTI.
Secondary objectives were the evaluation of the workflow and productivity of the
UF-1000i, by way of throughput, turn around time and performance of routine tasks.
Finally, the new Iris Diagnostics’ iChem®VELOCITY ™ automated urine chemistry
system was utilized to obtain chemistry analytes in an effort to fully evaluate all
parameters for UTI screening available from Iris Diagnostics.
The typical urine sample cultured for bacterial growth has an 80% chance of a
negative result5. In an effort to reduce this high negative rate, WBCs, Bacteria, RBCs,
epithelial cells and casts in urine have all been evaluated with regards to their
ability to predict a UTI successfully6. Both the iQ200 and the UF-1000i are able
to utilize these same parameters, although they have inherently different technologies.
While the iQ200 utilizes its Auto Particle Recognition (APR™) software to analyze
images taken of the sample particles, the UF-1000i relies on flow cytometry and subsequent scattergram analysis for particle identification. Another key difference between the two systems is the way they identify bacteria. Bacteria are defined in the
Bacteria category for the iQ200 as images of Bacteria that are recognized by the APR
and that are ≥3um. Bacteria <3um are classified in the All Small Particle (ASP) reporting category. The UF-1000i has a separate Bacteria channel that stains the nucleic
acid elements within bacteria while suppressing the non-specific staining of foreign
matter7. The microscopic particles of particular interest in this clinical assessment
include WBCs, Bacteria and ASP, as seen in a previous comparison of the Sysmex
UF-100 and the iQ2008. Additionally, two chemistry analytes (Leukocyte Esterase
and Nitrite) were also evaluated with the iChemVELOCITY for their ability to increase the NPV.
Conclusions
The overall evaluation of the two systems showed the iQ200 to be a better negative
predictor of UTI than the UF-1000i (NPV=92.7% vs. 86.6%, CFU > 105/ml). Adding
the chemistry analytes from the iChemVELOCITY (in addition to the ASP category
from the iQ200) enhanced the negative predictive value (NPV) from 72.9% to 77.5%
(CFU/ml >104) as well as from 92.7% to 93.7% (CFU/ml >105).
As a routine automated urinalysis system, the UF-1000i and the iQ200 showed
good agreement (± 1 grade) with respect to red blood cells (RBCs), white blood
cells (WBCs), epithelial cells, casts and unclassified crystals. Additionally, the
performance of the UF-1000i showed the same level of agreement (± 1 grade) for
RBCs, WBCs, epithelial cells, casts and unclassified crystals as seen between
the iQ200 and the UF-100, predecessor to the UF-1000i. Manual microscopic
review rate for the UF-1000i was high (60%) as compared to the iQ200 (0%) but
was consistent with previous experience with the UF-100 (27-50%).1,2 The manual
microscopic review rate difference (defined as the need for preparing the specimen on a glass slide for evaluation on a microscope) between the iQ200 and the
UF-1000i (0% vs. 60%) was significant and added to increasing the time,
4-fold (48 minutes vs. 3.78 hours), to run samples on the Sysmex UF-1000i
system compared to the iQ200 system even though they have comparable
throughput specifications (iQ200 + 101 samples/hr; UF-1000i = 100 samples/hr).
Additionally, the time for routine tasks on the UF-1000i (such as Daily Maintenance) is substantially longer than on the iQ200 (with or without the addition of the
iChemVELOCITY).
The overall evaluation of the two systems showed the iQ200 to be a better negative
predictor of UTI than the UF-1000i (NPV=92.7% vs. 86.6%, CFU = 105/ml).
Adding the chemistry analytes from the iChemVELOCITY (in addition to the ASP
category from the iQ200) enhanced the negative predictive value (NPV) from 72.9%
to 77.5% (CFU/ml >104) as well as from 92.7% to 93.7% (CFU/ml >105).
As routine automated urinalysis systems, the UF-1000i and the iQ200 showed
good agreement (± 1 grade) with respect to red blood cells (RBCs), white blood
cells (WBCs), epithelial cells, casts and unclassified crystals. Additionally, the
performance of the UF-1000i showed the same level of agreement (± 1 grade) for
RBCs, WBCs, epithelial cells, casts and unclassified crystals as seen between
the iQ200 and the UF-100, predecessor to the UF-1000i. Manual microscopic
review rate for the UF-1000i was high (60%) compared to the iQ200 (0%) but was
consistent with previous experience with the UF-100 (27-50%).1,2 The manual
microscopic review rate difference (defined as the need for preparing the specimen on a glass slide for evaluation on a microscope) between the iQ200 and the
UF-1000i (0% vs. 60%) was significant and added to increasing the time,
4-fold (48 minutes vs. 3.78 hours), to run samples on the Sysmex UF-1000i
system compared to the iQ200 system even though they have comparable
throughput specifications (iQ200 + 101 samples/hr; UF-1000i = 100 samples/hr).
Additionally, the time for routine tasks on the UF-1000i (such as Daily Maintenance) is substantially longer than on the iQ200 (with or without the addition of the
iChemVELOCITY).
Introduction
The Iris Diagnostic iQ200SPRINT Urine Microscopy System has been shown to be an
effective tool in screening for urinary tract infections (UTIs) with negative predictive
values (NPVs) ranging from 91.6%3 to 100%4. With the introduction of the Sysmex
UF-1000i Automated Urine Sediment Analyzer, there is a need for a direct comparison between the two systems to determine if their differing principles of operation
give either system an advantage in screening for UTI.
1
Materials and Methods
The reference laboratory, Western Health Sciences Medical Laboratory (Canoga
Park, CA), used for this evaluation regularly receives up to 150 urinalysis samples
per day. Of those samples, ~30% include orders for culture with identification
and sensitivity. Comparison testing was implemented at the Iris Diagnostics’
Clinical Evaluations laboratory (Chatsworth, CA) and correlated back to the manual
microscopy and urine culture results provided by the reference laboratory.
All manufacturers’ instructions were followed with regards to system calibration
and quality control methods. Procedures related to startup, maintenance and
shutdown were performed as recommended by the respective manufacturer’s
guidelines. Iris Diagnostics quality control materials utilized during the study
were the iQ200 Control/Focus, iChemVELOCITY IRISpec, and CA/CB/CC.
UF-1000i quality control material utilized during the study was the UFII (Latex)
Control Material.
Microscopic systems:
Microscopic analysis was performed on the Sysmex UF-1000i and Iris Diagnostics
iQ200SPRINT. The microscopic results for each instrument are as follows:
Urine chemistry system:
Iris Diagnostics’ iChemVELOCITY urine chemistry system and iChemVELOCITY
strips were used to run the urine chemistry results.
Specimens
Urine samples were obtained from the daily workload of the reference laboratory.
Upon receipt into the laboratory, each sample (with sufficient volume) was divided
up into two allocations, one for the reference lab and one for the evaluations lab. The
reference lab allocation was further divided into 2 parts for manual microscopy and
urine culture. The evaluation lab allocation was also separated but into two Becton
Dickinson (Franklin Lakes, NJ) Vacutainer Urine Preservative Tubes (#364992), due
to the need to transport the sample to a different location. Four hundred seventy-nine
(479) samples were analyzed for the microscopy, chemistry and culture evaluations.
Any extremely mucoid, viscous or grossly bloody specimens were excluded from
the sample set. Additionally, any samples with definitive culture results indicative of
contamination, as defined by a CFU/ml urine culture result between 104 and 105,
where 3+ organisms are found, were excluded from analysis.
Table 1.
Sysmex UF-1000i
Auto-Classification
of particles
5 total:
RBC, WBC,
Epithelial cells,
Hyaline Casts,
Bacteria
Flagged
6 total:
Small round cells,
Crystals, Pathological
Casts, Yeast-like cells,
Mucus
Sub-classification
of particles
iQ200 Series
12 total:
RBC, WBC, WBC Clumps,
Squamous Epithelial Cells,
Hyaline Casts, Unclassified
Casts, Non-Squamous
Epithelial Cells, Yeast,
Bacteria, Crystals,
Mucous, Sperm
Testing Procedure
Study activities including, but not limited to, sample handling, record keeping
and reporting were designed and carried out in compliance with standard HIPPA
regulations. These regulations were followed to protect patient privacy; specimens
were assigned a random identification code and all identifying information was
removed.
26 Total:
Unclassified Crystals:
Calcium Oxalate, Triple
Phosphate, Calcium
Phosphate, Leucine,
Amorphous, Uric Acid,
Calcium Carbonate,
Cystine, Tyrosine
The study protocol was divided into 3 sections:
Unclassified Casts:
Granular Casts, Cellular
Casts, Waxy Casts, Broad
Casts, Red Blood Cell Casts,
White Blood Cell Casts,
Epithelial Casts, Fatty Casts
1. Clinical Sample Correlation and Concordance
Clinical samples were analyzed by manual microscopy according to the
reference laboratory’s accepted testing protocol and according to
manufacturers’ recommendations for both the Sysmex UF-1000i and the iQ200/
iChemVELOCITY systems.
Yeast:
Yeast with
Pseudohyphae
For this evaluation, discrepant urine microscopy results were defined as any
pair of (same sample) results that did not agree within one level, or grade.
However, if both a negative and a low end positive result were found (while
technically within one grade agreement) the intent was to resolve the difference
between the contradictory answers. All discrepancies were resolved by repeating the sample and/or use of the manual microscopic result as the referee.
Non-Squamous
Epithelial Cells:
Renal Epithelial Cells,
Transitional Epithelial Cells
Others:
Trichomonas, Fat, Red Blood
Cell Clumps, Oval Fat Bodies
Unclassified: Dysmorphic
Red Blood Cells
2. UTI Screening Capability
Urine culture was performed according to the laboratory’s accepted protocols and included inoculation of 0.001ml sample onto both Blood agar and
MacConkey agar for 48 hr growth results. Classical media (i.e. Urea, Citrate,
TSA, MIO, Bile Esculin, Oxidase, Peroxidase, Bacitracin, Enterotube etc.)
provided organism identification while sensitivities were performed by the
Kirby-Bauer method.
2
As part of the evaluation, each set of results provided by the UF-1000i and the
iQ200 were analyzed and compared to urine culture results, provided by the
reference laboratory, to determine the ability of each system to accurately predict a negative result for the presence of a UTI. The samples were divided into
3 categories based on the colony forming units (CFU) from the culture results:
By comparing the time required for sample analysis, performance of daily maintenance and quality control procedures, the iQ200 saves a significant amount of time as
compared to the use of the UF-1000i running the same tasks. Due to the minimum
amount of time added by including the iChemVELOCITY in these same comparisons, the complete iRICELL (iQ200 and iChemVELOCITY) still saves a significant
amount of time as compared to the UF-1000i in running these tasks.
a. CFU < 10,000/ml considered negative
Microscopic performance
Assessment of agreement between the UF-1000i and the iQ200 was determined
through comparative agreement of sample results (± one grade) through the use of
EP Evaluator 8. The results of this direct system to system agreement, with 95%
confidence intervals, can be found in Table 2.
b.CFU of 10,000/ml to 100,000/ml may be considered positive, if a predominant organism was easily identified, or contamination if 3+ organisms
were found
c.CFU > 100,000/ml considered positive
Table 2.
Microscopic particles evaluated include WBCs, Bacteria, and ASP
(iQ200 only). The chemistry analytes Leukocyte Esterase and Nitrite from the
iChemVELOCITY were also evaluated in conjunction with the results from
the iQ200.
3.
Workflow/Timing
Timing studies were conducted analyzing:
 Routine Turn around Time (TAT)
 Time required to analyze and report 50 complete urinalysis results
Time required to perform routine tasks (Daily Maintenance,
Quality Control)
Daily logs were kept for all aspects of the study and included quality control results,
routine maintenance procedures, descriptions of any errors that occurred with steps
taken for resolution, and samples flagged for review were identified and processed
to obtain final results. Additionally, all service calls and manual review results were
recorded.
Particle
n=336
Agreement (%)
“Score” Method9
95% confidence
interval
RBCs
95.0
92.1 to 96.8%
WBCs
94.3
91.3 to 96.4%
Epithelial Cells
89.5
93.5 to 98.3%
Casts
96.7
92.9 to 98%
Unclassified Crystals
86.3
82.2 to 89.6%
Table 3.
Data Analysis
Direct system to system result comparison analysis was performed with the EP
Evaluator 8 Software Package9. Cross tabulations using 2 x 2 contingency tables
were performed to look at each system result as compared to its corresponding urine
culture result. Urine culture results were regarded as the legitimate, or gold
standard, result and calculations were made in line with both NCCLS guidelines10
and FDA Guidance11. Analyses were further performed using the Diagnostic Utility
Statistics software package12 to obtain verification of Sensitivity, Specificity, Negative
Predictive Value, Positive Predictive Value, False Negative Rate and Quality of the
Negative Predictive Power. 95% confidence intervals, instead of p values, were utilized
for reporting of the evaluation results in line with Altman, et al.13
UF 1000i Settings
Bacteria Rinse Cycles
104=0
105=0
Factory
Settings
106=1x
107=1x
108=1x
Results
To determine the alignment of results between the iQ200 and the UF-1000i systems,
EP Evaluator 8 was utilized for the direct system to system result analysis. Agreements
within 2 grades, or rather results within ± 1 grade, were determined. Bearing in mind
that this part of the overall clinical assessment is a comparison between two nonreference standards and the status of the patient condition is unknown (as determined
by a reference standard), the calculations of sensitivity and specificity would not be
technically relevant11 so they were not performed.
104=0
105=0
Customer
Settings
106=1x
107=2x
108=3x
For overall performance, there was good agreement of microscopy results between
the UF-1000i and the iQ200 with the iQ200 exhibiting a much lower manual microscopic review rate. Due to the percentage of samples analyzed on the UF-1000i which
required reflex to manual microscopy, the iQ200 showed better correlation to the
manual microscopy results versus the UF-1000i comparison to manual microscopy.
With the UF-1000i, a high manual microscopic review rate was experienced.
During the evaluation 60%, of the UF-1000i samples are flagged by the system for
manual microscopic review while the iQ200 required a manual microscopic review
3
of 0% for the same samples. Flagged specimens were those flagged by the UF-1000i
as a particle present but needing further identification (i.e. presence of a crystal
but a clinical need to identify the type) or the specimen needing further review due
to the results being out of the instrument set parameters. In order to correctly
ascertain the ability of the UF-1000i to run 50 abnormal samples, 2 tests were
implemented in order to take into account the systems ability to vary its number of
rinse cycles for the Bacteria channel. The first test utilized the factory
settings for the rinse cycles while the second test utilized the rinse settings obtained from a current UF-1000i user. See Table 3. The same samples were
run through each test with a total analysis time for the factory settings of 3.68 hrs,
56 minutes + manual review time. The Customer settings added an additional
3 rinses (at 2 minutes/rinse cycle) increasing the time to 3.78hrs, 62 minutes + manual
review time. The manual review time was calculated utilizing 15 minutes for sample
centrifugation plus 5 minutes per sample for microscopic review of the 30 flagged
specimens.
Running the same 50 samples on the iQ200 SPRINT took a total of 48 minutes
and included 85% on-screen review of the sample images. Adding the
iChemVELOCITY and making a complete iRICELL workcell increased the time by
only 2 minutes for a total of 50 minutes. Based on a daily workload of 150 samples
with customer settings for the Bacteria channel on the UF-1000i as compared to
running a complete iRICELL, the estimated total time savings each day is 2.95 hours;
a significant improvement in productivity in addition to getting the chemistry results
from the iChemVELOCITY.
UTI Screening Performance
Assessment of agreement between the microscopy systems as compared to the urine
culture results (with the categories CFU/ml > 104 and CFU/ml >105 as defined by
commonly accepted criteria14) were through the use of EP Evaluator 8. The results
were assessed based on their ability to correctly predict a negative result for culture
and the parameters of interest (WBCs, Bacteria and ASP) were adjusted to achieve
the best threshold values possible with statistical significance. The two chemistry
parameters were also evaluated although the Nitrite analyte showed no significance on
the negative predictive value. The results were then placed into the Diagnostics Utility
Statistics Software for further analysis. The False Negative Rate (FNR), the Quality
of the Negative Predictive Power, and the Likelihood Ratio (-) were all determined for
the thresholds shown in Tables 4 and 5.
Table 4.
105 CFU/ml
UF1000i
iQ200
n=378
(WBC ≥ 5/HPF,
105 CFU/ml)
(WBC ≥ 5/HPF,
Bact +)
iQ/iRICELL iQ/iRICELL
(WBC ≥ 5/HPF,
Bact +, ASP≥
7500, LE ≥ 25
leu/ul)
(WBC ≥ 5/HPF,
ASP≥ 7500, LE
≥ 25 leu/ul)
NPV
NPV=TN/
(TN+FN)
86.6%
92.7%
93.7%
91.1%
Sensitivity
Sen=TP/
(TP+FN)
70.8%
86.8%
91.5%
84%
FNR
FNR=#
FN/#TP
29.2%
13.2%
8.5%
16%
QNPP
52.1%
74%
77.4%
68.1%
Likelihood
Ratio (-)
+2.514
+4.955
+5.759
+3.966
Discussion
In an effort to accurately assess the value of a screening tool for UTI, as well as keep
within commonly accepted criteria for culture evaluation14, the urine culture results
were divided into 3 basic categories based on colony forming units (CFU) from the
culture results:
d.CFU< 10,000/ml considered negative
e.CFU of 10,000/ to 100,000/ml may be considered positive, if a predominant
organism was easily identified, or contamination if 3+ organisms were found
f. CFU> 100,000/ml considered positive
Analyzing the data of each of these three categories, using the previously mentioned
parameters and thresholds, allows for a good estimation of each system’s ability to
detect a possible UTI with readily apparent levels (CFU/ml >105) and possible lower
levels of infection (CFU/ml >104).
By approaching the data with a focus on the ability of each system to negatively
predict the presence of a UTI in a screening process, the typical diagnostic descriptors of Sensitivity [True Positive/ (True Positive + False Negative)] and Specificity
[True negative/ (True Negative + False Positive)] are no longer able to provide an
accurate picture. The ability to correctly screen out true negatives, and thus reducing the number of false negatives, becomes the focus and can best be described by
the Negative Predictive Value [ True Negative/(True Negative + False Negative)] and
the False Negative Rate (# of False Negatives/# of True Positives). Additionally, the
diagnostic value, as assessed by these negative predictors, can be further described
by the Quality of the Negative Predictive Power, or QNPP, (provides the value, in
percent, of performing the test vs. not performing the test) and the Likelihood
Ratio (-) (provides the odds that a negative result actually comes from a person without the disorder). By applying these diagnostic descriptors to the data and assessing
the systems according to the aforementioned culture criteria, the iQ200 had a better
NPV (72.9% vs. 65.8% CFU/ml >104 and 92.7% vs. 86.6% CFU/ml >105) a better
FNR (29.1% vs. 44.1% CFU/ml >104 and 13.2% vs. 29.2% CFU/ml >105), a better
QNPP (42.8% vs. 27.8% CFU/ml >104 and 74% vs. 52.1% CFU/ml >105) and a better
Likelihood Ratio (-)(+2.422 vs. +1.731 CFU/ml >104 and +4.955 vs. +2.514 CFU/ml
>105) then the UF-1000i for both readily apparent ( CFU/ml >105 ) and possible low
level infections (CFU/ml >104). By adding the only significant chemistry parameter,
Table 5.
104 CFU/ml
UF1000i
iQ200
iQ/iRICELL iQ/iRICELL
n=378
(WBC ≥ 5/HPF,
105 CFU/ml)
(WBC ≥ 5/HPF,
Bact +)
(WBC ≥ 5/HPF,
Bact +, ASP≥
7500, LE ≥ 25
leu/ul)
(WBC ≥ 5/HPF,
ASP≥ 7500, LE
≥ 25 leu/ul)
NPV
NPV=TN/
(TN+FN)
65.8%
72.9%
77.5%
71.6%
Sensitivity
Sen=TP/
(TP+FN)
55.9%
70.9%
82.1%
69.8%
FNR
FNR=#
FN/#TP
44.1%
29.1%
17.9%
30.2%
QNPP
27.8%
42.8%
52.4%
40%
Likelihood
Ratio (-)
+1.731
+2.422
+3.092
+2.265
4
Leukocyte Esterase, from the iChemVELOCITY, as well as the addition of the
ASP category from the iQ200 the values for NPV (77.5% vs. 72.9% CFU/ml >104 and
93.7% vs. 92.7% CFU/ml >105), FNR(17.9% vs. 29.1% CFU/ml >104 and 8.5%
vs. 13.2% CFU/ml >105), QNPP (52.4% vs. 42.8% CFU/ml >104 and 77.4% vs.
74% CFU/ml >105) and Likelihood Ratio (-)(+3.092 vs. +2.422 CFU/ml >104 and
+5.759 vs. +4.955 CFU/ml >105) increased above those for the iQ200 without these
values. These two additional parameters have, overall, a significant impact in the
ability to screen for UTI with a bigger effect on the CFU>104 sample categorization, thus demonstrating that the use of only WBCs and bacteria, the key indicators
available on the UF-1000i, for UTI screening is limited in the possible lower level
infections.
References
1.New Automated Urinalysis—Workcell Review. Multicare Medical Center,
Tacoma, Washington; Rita N. Hofberg, Brian D. Miller; 2008.
In addition to the UTI screening comparison, the overall system comparisons between
the UF-1000i and the iQ200 showed good agreement (± 1 grade) for all particles,
although the manual review rate for the UF-1000i was high (60% vs. 0%). Of
additional interest is the fact the agreements for all the particles between the
UF-1000i, as well as the manual microscopic review rates, were very similar to those
previously published between the iQ200 and the UF-1001,2. This implies that the only
difference the new UF-1000i system has is the bacteria channel that has shown no
distinct advantage.
4.Ledru S., Canonne J.P.; Comparison between IRIS iQ®200ELITE™ and microscopy for urinalysis and evaluation of performance in predicting outcome of urine
cultures[Translated from French journal article]; Annales de Biologie Clinique,
Volume 66, Number 5, September-October 2008.
Conclusions
The overall evaluation of the two systems showed the iQ200 is a better negative
predictor of UTI than the UF-1000i for both the readily apparent (CFU/ml >105)
and possible low level infections (CFU/ml >104). Adding the ASP and the chemistry
analyte from the iChemVELOCITY improved not only the NPV but also the FNR,
the QNPP and the Likelihood Ratio (-) with the most significant impact on the CFU/
ml >103 category, thus demonstrating that the use of only WBCs and Bacteria, the
only two key indicators available on the UF-1000i, for UTI screening is limited in the
possible lower level infections.
6.Davies E.M., Lewis D.A. Bacteriology of urine. In: Hawkey P., Lewis D.A., eds.
Medical Bacteriology. Oxford: Oxford University Press, 2004: 1-25.
As a routine automated urinalysis system, the UF-1000i and the iQ200 showed good
agreement (± 1 grade) with respect to red blood cells (RBCs), white blood cells
(WBCs), epithelial cells, casts and unclassified crystals. Additionally, the performance of the UF-1000i showed the same level of agreement (± 1 grade) for RBCs,
WBCs, epithelial cells, casts and unclassified crystals as seen between the iQ200 and
the UF-100, predecessor to the UF-1000i. Manual microscpic review rate for the UF1000i was high(60%) as compared to the iQ200 (0%) but was consistent with previous
experience with the UF-100 (27-50%).1,2 The manual microscopic review rate difference (defined as the need for preparing the specimen on a glass slide for evaluation on
a microscope) between the iQ200 and the UF-1000i (0% vs. 60%) was significant and
added to increasing the time, 4-fold (48 minutes vs. 3.78 hours), to run samples on the
Sysmex UF-1000i system compared to the iQ200 system. Additionally, the time for
routine tasks on the UF-1000i (such as Daily Maintenance) is substantially longer then
on the iQ200 (with or without the addition of the iChemVELOCITY).
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USA.
2.Clinical Assessment of the iRICELL Automated Urinalysis Workcell.
Pennsylvania, Brian D. Miller; December 2008.
3.Accordini, A. Conti, L. Gasparini, C. Motta, A Dalmazzo, M. Caputo; Automated
Microscopy and Screening of Bacteriuria [Translated from original presentation
in Italian]; 21 Congresso Nazionale SIMeL, Riva del Garda, 25 – 27 October
2007.
5.Kellogg J.A., Manzella J.P., Shaffer S.N. Schwartz B.B. 1987. Clinical relevance
of culture versus screens for the detection of microbial pathogens in urine specimens. Am J Med; 83: 739-745.
7.UF-1000i Instructions for Use, Sysmex Corporation, Kobe Japan.
8.F. Cerroni, F. Mancinelli, P. Cipriani + R. Barbanti + D. De Prosperis, P Cardelli;
Statistical Model That Supports Instruments in Assessment of Urinary Infection
[Translated from original presentation in Italian]; 21 Congresso Nazionale SIMeL
Riva del Garda, 25 – 27 October 2007.
10.NCCLS. User Protocol for Evaluation of Qualitative Test Performance; Approved
Guideline. NCCLS document EP12-A [ISBN 1-56238-468-6]. NCCLS, 940 West
Valley Road, Suite 1400, Wayne, Pennsylvania 19087-1898 USA, 2002.
11.Center for Devices and Radiological Health. Guidance for Industry and FDA
Staff. Statistical Guidance on the Reporting Results from Studies Evaluating Diagnostics Tests. March 13, 2007. www.fda.gov/cdrh/osb/guidance/1620.pdf.
12.Watkins, M. W. (2009). Diagnostic Utility Statistics [Computer software]. Phoenix, AZ: Ed & Psych Associates.
13.Altman, D.G and Gardner, M.J. 1986. Confidence intervals rather thean P values:
estimation rather than hypothesis testing. British Medical Journal:292:746-750.
14.Isenberg H.D., ed. Clinical Microbiology Procedures Handbook, 2nd edition.
Chapter 3.12 Urine cultures. American Society for Microbiology, ASM Press
2004; Washington, DC.
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