Macherey-Nagel URYXXON 500 User Manual Download Page 32

Page: 32 / 133

Instruction for use URYXXON

500

Instruction for use URYXXON

500 V 2.1 / 01.23

17.5.3 Assay reportable range

Blood: neg. ·  10 ·  50 ·  250 erythrocytes/μL
Urobilinogen: norm. ·  2 ·  4 ·  8 ·  12 mg/dL
Bilirubin: neg. ·  1 ·  2 ·  4 mg/dL
Protein: neg. ·  30 ·  100 ·  500 mg/dL
Nitrite: neg. ·  pos.
Ketones: neg. ·  25 ·  100 ·  300 mg/dL
Glucose: neg. ·  norm. ·  50 ·  150 ·  ≥ 500 mg/dL
pH: 5 ·  6 ·  6.5 ·  7 ·  8 ·  9
Density: 1.000 ·  1.005 ·  1.010 ·  1.015 ·  1.020 ·  1.025 ·  1.030 g/mL
Leukocytes: neg. ·  25 ·  75 ·  500 leukocytes/μL

17.5.4 Cut-off concentration

The Cut‑Off‑Concentration (Medical decision point) has been

defined as the concentration, where minimum 50% of the results

are positive.

Parameter

Cut-off concentration URYXXON

500

Blood

approx. 4 Ery/µL

Urobilinogen

approx. 2.0 mg/dL

Bilirubin

approx. 0.8 mg/dL

Protein

approx. 15 mg/dL

Nitrite

approx. 0.05 mg/dL

Ketones

approx. 10 mg/dL

Glucose

approx. 35 mg/dL

Leucocytes

approx. 10 Leu/µL

17.6 Changing the cut-off points

NOTICE

Changes in the cut‑off points are a major intervention for the
instrument’s measuring procedure. Changes in the cut‑off
points will alter the measuring results. Such results have to
be verified. If you do not have the capability of verifying such
new measurements, we strongly recommend not changing
the cut‑off points. MACHEREY‑NAGEL cannot guarantee any
measurements made with changed cut‑off points

(see chapter

17.10 General usage comments, page 33)

It is possible to change the instrument’s pre‑defined cut‑off

points. If you want to make changes to the cut‑off points, contact

MACHEREY‑NAGEL directly.

17.7 Comparative study

In a comparative study 240 urine samples were evaluated with

urine test strips on the URYXXON

500 and similar competitor

instruments.
The results of the study are summarized in the following table.
The exact agreement for parameters blood, urobilinogen, bilirubin,

protein, nitrite, ketones, glucose, pH and leukocytes amounts to

≥ 80 % in every case. For parameter density agreement ± 1 bin

amounts to 88 % and 43 % when compared to two different

competitor products. Agreement ± 2 bins amounts to 100 % and

85 %, respectively. Overall average exact agreement is 91 % and

86 % when compared to competitor products. Overall agreement

± 1 bin amounts to 100 % and 98 %.

Parameter

Comparison

URYXXON

500 –

Competitor 1 ***

URYXXON

500 –

Competitor 2 ***

exact
agreement

agreement
± 1 bin

exact
agreement

agreement
± 1 bin

Blood

84 %

100 %

86 %

100 %

Urobilinogen

94 %

100 %

98 %

100 %

Bilirubin

91 %

100 %

84 %

100 %

Protein

92 %

100 %

90 %

100 %

Nitrite

92 %

N/A

97 %

N/A

Ketones

99 %

100 %

97 %

100 %

Glucose

95 %

100 %

94 %

100 %

81 %

100 %

87 %

99 %

Density

88 %*

100 %**

43 %*

85 %**

Leukocytes

90 %

100 %

85 %

99 %

overall average

91 %

100 %

86 %

98 %

* this value represents agreement ± 1 bin
** this value represents agreement ± 2 bins
*** similar competitor devices with similar intended purpose (reflectometric

device for automatic read‑out of urine test strips)

Diagnostic specificity, diagnostic sensitivity, negative predictive

value and positive predictive value for parameters blood,

urobilinogen, bilirubin, protein, nitrite, ketones, glucose and

leukocytes are summarized in the following table. Overall, diagnostic

specificity is 95 % and diagnostic sensitivity is 98 %. The average

negative predictive value is 98 %; the average positive predictive

value is 86 %. Values for the parameters pH and density cannot

be calculated because these parameters do not allow negative /

positive interpretation.

Parameter

Diagnostic
specificity