Possible personal contamination? - (Sep/14/2006 )
At work, I process blood samples that are usually infected with hepatitis. I always wear PPE and am careful, but there is an issue of possible personal contamination that is really bothering me. Here is what my coworker and I normally do: put on PPE, process blood sample, log the information in the lab book, remove PPE, then wash our hands. My is question is: could the lab book be contaminated by the blood specimens that we handle? After completion of the task, my coworker and I handle the lab book with our bare hands, without giving a though to possible contamination. Should I be concerned about contamination? (I certainly do not wish to become infected!) Or am I over-reacting?
I assume everything in our TC/wet labs is potentially contaminated. We deal with thousands of patient samples (blood and other fluids) and need to record all our specimen handling details. It's probable that pipette guns, pens and everything else we handle in the lab while wearing gloves is potentially contaminated. Wear gloves while you're in the lab, wash your hands thoroughly when you leave, particularly if you have been handling things without gloves.
Probably the most important thing I can suggest is to get yourself vaccinated against Hep B. In fact, you can't start working in our institution unless you've been offered vaccination, which is provided free to all staff, including monitoring of antibody titre levels. There's no need to be paranoid about infection. If you follow basic good practice you will be fine.
in answer to your question, yes, your log book may be contaminated because of your handling.
what i do is remove my gloves before handling the book and pen. if this is too expensive in gloves and there are at least two of you then one could log while the other handles the specimens and alternate tasks each time.
if I'm not wrong, hepatitis B (I don't know which one you study) can survive several days.
You should not bring your lab book in this room.
Mine is always in my office , I use a draft book in the lab (in case something is splitted on) and report each day the data in my lab book.
I know also that writing on draft papers is a good way to loose data if you do not report them immediately, but you need to find a compromise.
it's better to write important experiment steps/notes or whatever u need on the whiteboard of the lab (if there is one), to avoid contamination...the same thing for results .....and later u can copy them to your book
Thanks everone for your replies--I've found them very helpful! Keeping the lab book away from the specimen processing area and logging in the information later is very good advice. It looks like everyone agrees that the lab book may be contaminated. This makes me a kind of worried. Since we have been touching the lab book with our bare hands, have we then been spreading contamination around to other surfaces? Is it possible that there could be trace amounts of contamination in the office or in my home or car? Further, whenever I have rubbed my eyes or eaten food after handling the book, have I exposed myself to infection that way? The blood I handle is usually infected with hep b or hep c. I am already vaccinated against hep b, but since there is no vaccine for hep c, I still have that vulnerability. I have read that the survival time of hep c on a surface is 16 hours up to four days. Elsewhere, I have read that it can survive on a surface up to 14 days. I am concerned about my health and I think I will get myself tested for hep c.
J Clin Microbiol. 1992 April; 30(4): 757-763
Survival of hepatitis A virus on human hands and its transfer on contact with animate and inanimate surfaces.
J N Mbithi, V S Springthorpe, J R Boulet and S A Sattar
Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ontario, Canada.
The survival of hepatitis A virus (HAV; strain HM175) on the hands of five volunteers was determined by depositing 10 microliters of fecally suspended virus on each fingerpad and eluting the inoculum after 0, 20, 60, 120, 180, and 240 min. The amount of virus recovered from each fingerpad at 0 min was approximately 6.0 x 10(4) PFU. At the end of 4 h, 16 to 30% of the initially recoverable virus remained detectable on the fingerpads. HAV inocula (10 microliters; approximately 1.0 x 10(4) PFU) placed on fingerpads or 1-cm-diameter metal disks were used to determine virus transfer to clean surfaces upon a 10-s contact at a pressure of nearly 0.2 kg/cm2. When the inoculum was dried for 20 min, virus transfer from fingerpad to fingerpad, fingerpad to disk, and disk to fingerpad ranged from 2,667 to 3,484 PFU, while 0 to 50 PFU could be transferred after 4 h of drying. Elevation of the contact pressure alone from 0.2 to 1.0 kg/cm2 resulted in an approximately threefold increase in the amount of virus transferred. Incorporation of friction (10 half turns of the finger during 10 s of contact) with the low and high levels of pressure gave two- and threefold increases in the PFU of virus transferred, respectively. Pressure and friction were found to significantly affect HAV transfer (F = 33.98; P less than 0.05), irrespective of the mode of transfer used. No statistically significant interaction was observed between mode of transfer and pressure or friction. The findings of this quantitative study suggest that human hands may play an important role in the direct as well as the indirect spread of HAV.