Performance Data - Siemens IMMULITE 2000 Manuel D'instructions

therefore yield androstenedione results
which fall above the upper central 95%
1,2
limit.
Diurnal variation has been observed. For
example, in 11 healthy men 18 to 30 years
of age, the mean 24-hour
androstenedione concentration was
0.93 ng/mL, with a circadian amplitude
equaling 42% of the mean. The major
acrophase occurred in the morning at
07:10 hours; the major nadir occurred in
the evening at 23:00; and there was a
secondary acrophase at 16:35. The 95%
confidence interval for acrophase/nadir
13
was 68 minutes. Accordingly, the time of
collection should be noted.
It should be remembered that exercise
can have a significant impact on
circulating androstenedione levels. Thus,
in a study of 18 professional soccer
players, the mean androstenedione
concentration increased from a baseline of
approximately 0.9 ng/mL to 1.8 ng/mL at
end of game, declining to 0.7 ng/mL ninety
minutes afterwards. 14 In another study, the
mean androstenedione level for 20
moderately trained men increased
significantly, from a baseline mean of
1.11 ng/mL, to 1.41 ng/mL five minutes
15
after a one-hour swim.
Steroid metabolites have been tested for
crossreactivity in this assay (see
"Specificity" section). However, the steroid
metabolites tested are not exhaustive;
therefore crossreactivity to all steroid
metabolites can not be ruled out.
Androstenedione results may be falsely
elevated in samples obtained from
patients being treated with Spironolactone
due to cross-reactivity. Use of this assay is
not recommended for patients undergoing
therapy with Spironolactone.
Heterophilic antibodies in human serum
can react with the immunoglobulins
included in the assay components causing
interference with in vitro immunoassays.
[See Boscato LM, Stuart MC. Heterophilic
antibodies: a problem for all
immunoassays. Clin Chem 1988:34:27-
33.] Samples from patients routinely
exposed to animals or animal serum
products can demonstrate this type of
interference potentially causing an
anomalous result. These reagents have
been formulated to minimize the risk of
interference; however, potential
4
interactions between rare sera and test
components can occur. For diagnostic
purposes, the results obtained from this
assay should always be used in
combination with the clinical examination,
patient medical history, and other findings.

Performance Data

See Tables and Graphs for data
representative of the assay's performance.
Results are expressed in ng/mL. (Unless
otherwise noted, all were generated on
serum samples collected in tubes without
gel barriers or clot-promoting additives.)
Conversion Factor:
ng/mL × 3.4916 → nmol/L
Reportable Range: 0.3–10 ng/mL
(1.04 to 35 nmol/L)
The assay is traceable to an internal
standard manufactured using qualified
materials and measurement procedures.
Analytical Sensitivity: 0.3 ng/mL
(1.0 nmol/L)
Precision: Samples were assayed in
duplicate over the course of multiple days,
for a total of 40 runs and 80 replicates.
(See "Precision" table.)
Linearity: Samples were assayed under
various dilutions. (See "Linearity" table for
representative data.)
Recovery: Samples spiked 1 to 19 with
3 androstenedione solutions (10, 40 and
100 ng/mL) were assayed. (See
"Recovery" table for representative data.)
Specificity: The antibody is highly specific
for androstenedione, with an extremely
low crossreactivity to other naturally
occurring steroids or therapeutic drugs
that may be present in patient samples.
(See "Specificity" table.)
Bilirubin: Samples spiked with 100 and
200 mg/L of conjugated and unconjugated
bilirubin were analyzed. Bilirubin may
interfere with the assay, causing
elevations. (See "Bilirubin" table.)
Hemolysis: Samples spiked with 135,
270 and 540 mg/dL of hemoglobin were
analyzed. Hemolysis may interfere with
the assay, causing elevations. (See
"Hemolysis" table.)
Lipemia: May cause a depression of
values. (See "Lipemia" table.)
IMMULITE 2000 Androstenedione (PIL2KAO-23, 2021-04)