Interpretation Of Results - Alere TestPack+Plus hCG Urine Manual Del Usuario

INTERPRETATION OF RESULTS

On Board Controls
Alere TestPack hCG Urine utilises four On Board Controls to ensure the
TM
assay is functioning properly.
• The Positive On Board Control (POS CTL "√") indicates
that both the antibody-colloid complex and capture
antibody systems are functional. The POS CTL "√" must
appear for the result to be valid.
• The Negative On Board Control (NEG CTL "X") indicates
that the test specimen may contain a non-specific entity
that could cause a false positive result. If the NEG CTL "X"
appears in the Result Window, the result is invalid.
• The Minus Sign "–" indicates that migration of the specimen has occurred.
The Minus Sign "–" must appear for the result to be valid.
• The End of Assay Window must change to a red/pink colour, which
indicates that the test is complete and ready to read. The End of Assay
colour change must occur for the result to be valid.
Patient Bar
EN
Positive Result
A positive result consists of one vertical line (Patient Bar) and
one horizontal line (Minus Sign) in the Result Window forming
a Plus Sign "+". Pink/red colour (darker than the background)
on the Patient Bar is interpreted as a positive result even if it
has less colour than the Minus Sign. Randomly occurring red dots should not
be evaluated in the interpretation of results.
Negative Result
A negative result is indicated by a horizontal line (Minus Sign
"-") in the Result Window. A negative result means that no
hCG was detected, or that the levels of hCG in the specimen
were below the detection limit of the assay.
Weak positive results may occur with hCG levels below 25mIU/ml. It is good
laboratory practice to resample and retest these weak positive specimens
after an additional 48-72 hours. The use of controls at hCG levels near the
assay sensitivity may guide in the interpretation of weak positive results.
The reaction area may, on occasion, exhibit outlines. An outline can be
described as a colourless area which surrounds all or part of the Patient
Bar. If outlines are present, an impression of the Patient Bar may be seen.
However, in the absence of hCG (negative specimens) this impression is
comparable to the background and should be interpreted as a negative result.
Specimens with high levels of hCG may yield colour on the Patient Bar as
quickly as 1 minute after specimen addition. Specimens with levels of hCG
at or above the level of sensitivity of the assay remain positive with time.
Specimens with levels of hCG below the sensitivity of the assay may yield
Minus Sign some colour on the Patient Bar with time however the test should be read 5
minutes after addition of sample.
EXTERNAL QUALITY CONTROL
Good laboratory practice recommends the use of control materials to ensure
proper kit performance. Each laboratory should refer to guidelines established
internally and by local, national or other accrediting organisations.
Due to variation in analyte composition and/or matrices, external quality
control materials and proficiency survey samples may not elicit identical
results across all hCG assays. Each laboratory needs to determine the
suitability of each control material for specific immunoassays and validate the
material prior to use.
LIMITATIONS OF THE TEST
1. Positive results from very early pregnancy may later prove negative
due to natural termination of the pregnancy. This is estimated to occur
in 31% of all conceptions
pregnancy test such as Alere
results be retested with a first morning urine specimen taken 48-72
hours later.
2. A negative result may be obtained if the urine specimen tested is too
dilute.
3. If a negative result is obtained and pregnancy is still suspected, the
patient should be retested 48-72 hours later using a first morning urine
specimen.
4. Abnormal pregnancies (e.g. ectopic) may produce lower concentrations of
hCG than expected for a given gestational age. Abnormal pregnancy
cannot be distinguished from normal pregnancy by hCG levels alone
5. hCG remains elevated for a time after pregnancy
out fewer than 3 weeks after giving birth, or 9 weeks after natural loss or
termination, may need further evaluation.
6. A number of conditions other than pregnancy can cause elevated levels of
urinary hCG, e.g. menopause, ovarian cysts, trophoblastic disease, and
certain non-trophoblastic neoplasms
7. Occasionally, specimens containing <25mlU/ml hCG may test positive.
8. Drugs containing hCG may interfere with Alere
and produce misleading results.
3
6 . It is recommended when using a sensitive
TM TestPack hCG Urine that weak positive
7,8 .
9 . Pregnancy tests carried
10 .
TM TestPack hCG Urine