Immunochromatographic test for prostate specific antigen detection

Description

BLUESTAR® Identi-PSA is a rapid qualitative test in a device for PSA detection from traditional biological samples (serum, plasma, or blood), but also from sperm samples collected with a swab either on the clothes or on the body of the presumed victim of a sexual assault.

BLUESTAR® Identi-PSA is perfectly suitable for use in forensic medicine:

• Highly sensitive: detects PSA levels higher than or equal to 4 ng/ml.

• Reliable

• Fast: reacts within 10 minutes.

• Easy compared with a traditional ELISA method.

Contents of a BLUESTAR® Identi-PSA test

Each Identi-HEM test includes the following:

• 1 collection bottle containing 1 ml extraction buffer for the sample

• 1 sterile swab

• 1 test device.

How to use the test

The sample to be tested is transferred into the tube with extraction buffer. This mixture is added drop by drop into the well of the test device. A positive sample is typically detected within 10 minutes.

A single wine-colored line in the "C" area means the testing liquid is working fine but no prostate specific antigen has been detected while two wine-colored lines mean the test has worked properly and has detected PSA.

Principle

The prostate specific antigen (PSA) is an intracellular glycoprotein (molecular weight: 34,000 daltons) only synthesised by the male prostate gland and in seminal plasma.

This protein is now used by the forensic medicine as a choice marker to detect sexual assaults, even when they are committed by men who had vasectomy.

BLUESTAR® Identi-PSA is a rapid qualitative assay for PSA detection from traditional biological samples (serum, plasma, or blood), but also from sperm samples collected with a swab either on the clothes or on the victims’ bodies.

The method employs a unique combination of monoclonal dye conjugate (mouse) and monoclonal antibodies (solid phase) to selectively identify PSA antigen in the samples, with a high degree of sensitivity.

As the test sample flows through the absorbent paper, the labelled antibody-dye conjugate binds to the antigen, thus forming an antigen-antibody complex. This complex binds to the anti-PSA antibodies in the positive reaction zone (T) and produces a wine-coloured line if the PSA antigen level is higher than 4 ng/ml. If there is no antigen, no line appears in the test zone.

The reaction mixture continues flowing through the absorbent paper, past the test zone and the control zone (C). Unbound conjugate binds to the reagents in the control zone, producing a wine-couloured band indicating that the reagents are functioning correctly.

Accuracy

An assessment of the BLUESTAR® Identi-PSA test was performed in 1997 in order to use it in forensic medicine. The publication of these results shows that the BLUESTAR® Identi-PSA test is perfectly suitable for this use as far as sensitivity, specificity, and feasibility are concerned. The test offers both very high sensitivity and high rapidity, as well as simplicity compared with a traditional ELISA method.

Reproducibility

Intra-assay: Within run precision was determined by using 10 replicates of three specimens containing 0, 5 and 10 ng/ml of PSA. The negative and positives values were correctly identified 100% of time.

Inter-assay: Between run precision was determined by using the same three specimens of 0, 5 and 10 ng/ml of PSA in 10 independent assays and with three different lots of reaction device over a 6 months period. Again, the negative and positive values were correctly identified 100% of time.

Sensitivity

The BLUESTAR® Identi-PSA test can detect PSA levels higher than or equal to 4 ng/ml according to the international PSA standard (CRM 613 N°1004 from the European Standard Office, Belgium 1998). However, some samples containing less than 5 ng/ml may cause positive results.

Hook effect

Some samples containing very high PSA levels (up to 10 μg/ml) constantly caused positive results. However, some negative sperm samples caused positive results after 1/100 or 1/1,000 dilution. In case of doubt for some samples, it is then necessary to make another assay after 1/100 or 1/1,000 dilution.

Storage temperature limits

All the components of the BLUESTAR® IDENTI-PSA test have a storage temperature range comprised between +4°C and 30°C.

Ordering BLUESTAR® IDENTI-PSA

Box of 24 tests. Order code # VD-PSA-24

Each box includes 24 collection tubes, 24 sterile swabs, 24 BLUESTAR® Identi-PSA tests devices, and 1 users instructions sheet.

Box of 6 tests. Order code # VD-PSA-6

Each box includes 6 collection tubes, 6 sterile swabs, and 6 BLUESTAR® Identi-PSA tests devices, and 1 users instructions sheet.