Item Brochure

QUALITY CONTROL
Internal Quality Control
Several procedural controls are incorporated into each OSOM Card Pregnancy Test for routine
quality checks.
The same labeled conjugate antibody results in the appearance of both the test and the control
bands. The appearance of the control band in the results window is an internal positive procedural
control which validates the following:
Test System: The appearance of the control band assures that the detection component of both the test
line and control line is intact, that adequate sample volume was added and that adequate capillary
migration of the sample has occurred. It also verifies proper assembly of the Test Device.
Operator: The appearance of the control band indicates that an adequate volume of fluid was
added to the sample well for capillary migration to occur. If the control band does not appear
at the read time, the test is invalid.
The clearing of the background in the results area may be documented as a negative procedural
control. It also serves as an additional capillary flow control. At the read time, the background
should appear white to light gray and not interfere with the reading of the test. The test is invalid
if the background fails to clear and obscures the observation of a distinct control band.
If the control band fails to appear with a repeat assay, do not report patient results. Contact Sekisui
Diagnostics for Technical Service: Tel [phone] (U.S. Customers only)
External Quality Control
Sekisui Diagnostics recommends that external hCG controls be run with each new lot, and with each
new untrained operator. The OSOM hCG Urine Control (Catalog Number 134) is designed for
this purpose. Quality Control requirements should be established in accordance with local, state and
federal regulations or acreditation requirements.
PROCEDURAL NOTES
• If specimen has been stored refrigerated, allow it to warm to room temperature before use.
• Several tests can be run at the same time. Use a new pipette with each test to avoid
contamination errors.
LIMITATIONS IN hCG TESTING
• This assay is capable of detecting only whole molecule (intact) hCG, which is the predominant form of
hCG in early pregnancy. It cannot detect the presence of hCG fragments or free subunits.
• In later term pregnancies (generally beyond the first trimester), occasional urine samples can contain
very high levels of hCG fragments. Therefore, the OSOM Card Pregnancy Test is most effective when
used for the detection of pregnancy in its earlier stages.
• For diagnostic purposes, hCG test results should always be used in conjunction with other methods
and in the context of the patient’s clinical information (e.g., medical history, symptoms, results of
other tests, clinical impression, etc.). Ectopic pregnancy cannot be distinguished from normal
pregnancy by hCG measurements alone.
(2,3)
• If the hCG level is inconsistent with, or unsupported by, clinical evidence, results should also be
confirmed by an alternative hCG method. Test results should be confirmed using a quantitative
hCG assay prior to the performance of any critical medical procedure.
• Interfering substances may falsely depress or falsely elevate results. These interfering substances may
cause false results over the entire range of the assay, not just at low levels, and may indicate the
presence of hCG when there is none. As with any immunochemical reaction, unknown interferences
from medications or endogenous substances may affect results.
• Infrequently, hCG levels may appear consistently elevated and could be due to, but not limited to,
the presence of the following:
(4–7)
Trophoblastic or nontrophoblastic neoplasms: abnormal physiological states that may falsely
elevate hCG levels.
(8,9)
This test should not be used in the diagnosis of these conditions.
hCG like substances
• Because of the high degree of sensitivity of the assay, specimens tested as positive during the
initial days after conception may later be negative due to natural termination of the pregnancy.
Overall, natural termination occurs in 22% of clinically unrecognized pregnancies and 31% of
other pregnancies.
(10)
In the presence of weakly positive results, it is good laboratory practice to
sample and test again after 48 hours.
• If the test band appears very faint, it is recommended that a new sample be collected 48 hours later
and tested using another OSOM Card Pregnancy Test Device.
• Dilute urine specimens may not have representative levels of hCG.
• Detection of very low levels of hCG does not necessarily indicate pregnancy
(4)
as low levels of hCG
can occur in apparently healthy, nonpregnant subjects.
(11,12)
Additionally, post-menopausal specimens
may elicit weak positive results due to low hCG levels unrelated to pregnancy. In a normal pregnancy,
hCG values double approximately every 48 hours.
(13)
Patients with very low levels of hCG should be
sampled and tested again after 48 hours, or tested with an alternative method.
• Some antipsychotic agents/drugs are known to cause false positive results in pregnancy tests.
(14)