Hello everyone!! Before i start talking about my attachment, i would like to wish all my Muslim frenz Selamat Hari Raya!! We shall go visiting one day alryte??

So this week, i am going to talk about the stool occult blood test and OC Light test.

Stool occult blood test

Introduction – To detect occult blood in stool

Principle of analysis - When stool specimens containing occult blood are applied to Hemoccult SENSA test paper, which is impregnated with guaiac, the hemoglobin portion of the occult blood comes in contact with the guaiac. When the Hemoccult SENSA peroxide developing solution is added, a guaiac peroxidase like reaction occurs. Oxidation of guaiac becomes visible by the appearance of a blue color within 30 seconds. A food that contains substances with peroxidase activity may cause false positive results.

Specimen – Stool

Reagents –

Hemoccult SENSA test slides
Hemoccult developing reagent

Retrieved from : http://www.beckman.com/products/rapidtestkits/hemoccultsensa.asp

Method –

1) Apply a very thin smear of stool inside section 1 and 2 with an applicator stick.

2) After 3-5 minutes, open the perforated section on the back of the slide.

3) Apply 1 drop of Hemoccult SCREEN developing reagent to the positive and negative well each and 2 drops to the reaction wells.

4) Read results after 30 seconds and before 1 minute.

Interpretation –

Read the results only when the controls give the correct color after the addition of the developing reagent.

• Positive – Traces of blue colors in either one or both of the reaction wells

• Negative – No indication of blue color in either one or both of the reaction wells

Positive stool samples are confirmed using the OC Light Occult Blood Method.

Limitations of procedure –

Hemoglobin is not usually found in the stool of healthy individuals. Its presence indicates bleeding in the gastrointestinal tract. Causes include tumors. Tumors are common in the elderly and this test is used as a screen to select patients for further invasive investigation.

Stool OC Light

Introduction – The OC Light method is used to confirm the positive cases by the Hemoccult SENSA method.

Principle of analysis – The OC Light is designed to measure human hemoglobin in fecal samples. The OC Light immunochromatographic test has a test detection range from 10µg to 100mg/g of feces. The test strip reacts only with human hemoglobin and does not react with hemoglobin of other animal origin.

Specimen - Stool

Reagents -

OC Light Sampling Bottles

OC Light Strips

Retrieved from : http://www.eiken.co.jp/en/product/index.html

Method -

1) Remove the green cap from the sampling bottle and dilute the stool inside the bottle.

2) Remove the white cone nozzle.

3) Insert the strip into the sampling bottle from the dip slide.

4) Read test result, presence of a blue line at the lower and upper center of the strip after 5 minutes.

Interpretation –

Read the result only when the controls give the correct color after the addition of the developing reagent.

Positive result – Presence of blue line at the lower and upper center of the strip may be considered positive.

Negative result – Presence of blue line only at the upper center of the strip is negative.

Equivocal result – No blue in line in both the lower and upper center of the strip or at the lower center of the strip only should be considered equivocal. Such samples should be retested by changing OC Light test strip.

That's all for now peepz!!

Before i sign off, i would like to say sorry if i have not answered any of your questions regarding my last two posts.. It's been hard for me to get access to the internet. I will try my best to reply to all the questions ASAP.. Really sorry especially to Ms Chew. I hope i have not been penalized by my lack of participation. I will try to participate more often once i got my laptop soon.. Sorry once again..

Toodles~~

** Sofie **