Collection and Dispatch of material for analysis

COLLECTION AND DISPATCH OF MATERIAL FOR ANALYSIS 
  • Veterinarians must possess knowledge of collection and dispatching of toxicological specimens to the laboratory. The final proof of poisoning lies in the detection of a significant quantity of  toxic agent in the body of the animal .
  • In all poisonous cases, chemical analysis of the biological specimen is essential to know the cause of death or illness. The veterinarian should know the salient points in collection and dispatch of toxicological specimen to a laboratory.
  • History of a case is very important in diagnosis of poisoning which includes number of animals in the farm, number of affected animals, method of feeding, type of feed, regularity of feeding, changes in feeding, whether pasture is sprayed with pesticides or fertilizers etc .
  • Samples for toxicological analysis during post-mortem examination.
  • In case of small animal (poultry, small dogs, cats, piglets, wild animals, etc.), the whole cadaver should be sent unopened. In pigs, sheep, larger dog, etc., tied –off stomach and tied- off parts of intestine are send separately (not in the same container). In the larger animals (horses and cattle), the samples are sent according to the size of the animals.

Tissue required for analysis

  • Blood : Collect contamination free blood sample from the animal. Prefer heart blood but peripheral blood is also acceptable. But do not “scoop up” the sample from the body cavity since this blood is usually contaminated with fluids from the cavity and/or the stomach contents. Usually 100 ml of sample is sufficient for routine studies.
  • Brain: Collect atleast 50 g of brain tissue. It is useful in the demonstration of alcohol, volatile and lipid soluble poisons.
  • Liver : A sample of 100 g is a minimal requirement. Majority of toxicants are found in the  tissue. In many cases, the liver may be the only tissue in which the toxic substance will be found in sufficiently at high concentration for absolute identification and quantitation.
  • Kidney: Take the equivalent of one kidney for analysis. This is the tissue of choice for most metals and sulphonamides.
  • Lung: Take atleast 100 g of lung. This tissue will be useful in fatalities due to substance by inhalation.
  • Bone: Collect 100g of bone if there is any indication that poisoning is due to any pesticide or metal. In case of chronic poisoning by fluorine compounds, send affected parts of bones and teeth.
  • Hair andFingernails : These specimens are taken if chronic metal poising is suspected, especially chronic arsenic poisoning
  • Adipose tissue: Take a minimum sample of 50 g. It is suitable for pesticide and drugs like Thiopental, Glutathemide, etc.,
  • Urine: Collect all the available urine (0.5 liter) and if bladder is empty submit it as such (intact). Urine often provides a concentrated relatively unadulterated form of a poison and its metabolites.It is applicable to a variety of preliminary screening tests.
  • Bile: Do not open the gall bladder at the time of necropsy but, rather, remove it intact and place into a separate container.
  • Stomach and Contents : Ligate the stomach at both ends and send it undisturbed to the laboratory. Drugs and chemicals may be found intact in cases of over dosage.
  • In addition to above it is also necessary to send for analysis the vomitus, faeces, urine, and milk if the poison is excreted via the mammary gland.
  • Materials other than Tissue : Retain all the material assumed to have caused the poisoning besides the cadavers and parts of organs. These are remains of fodder in the trough and around it, suspicious litter, samples of admixtures and salt (about 100 g), about 2 liters of water from the trough and drinkers, samples of wall paints, disinfectants, fertilizers, insecticides and etc.

Dispatch of material

  • Send each organ in a separate container clearly labeled with date, name and address of sender, particulars of organ, species and details of any preservative used. A full report of the clinical and post-mortem finding and also suspected poisons should accompany the samples.
  • The best containers are screw –capped polyurethane jars. Glass jars or pickle bottles, thoroughly cleaned, dried and fitted with air tight seal are satisfactory, but should be carefully packed to avoid any breakage. Do not use rubber closer rings as they contain compounds which may contaminate the sample. Test the polythene bags, if used, to make sure that they do not leak. Pack the dry material which is not liable to damp in new, strong, unused plastic bags. Place glass containers in rigid boxes (cartons) well padded with wood shaving, hay or saw – dust.
  • Always treat the parcel as infectious material so mark it with a black cross indicating that the content is infectious. Label the parcel “urgent” “Handle with care” and “keep away from food stuffs” Seal and dispatch the jars/parcels in such a way that they cannot be tampered en-route .
Last modified: Sunday, 25 September 2011, 10:05 AM