Toxicovigilance
Occupational Health 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

3. Analytical Laboratory Testing:

 
 
      Considering the type of poisonings prevalent in the area, laboratory investigations have been standardized with the voluntary support of experienced biochemists and chemists. Only those tests which are relevant, economical and have a quick turnaround time, and those which make a difference in emergency management of poisoning, have been developed. All tests are done with standard laboratory reagents. Methods used are:High Performance Liquid Chromatography (HPLC), Thin-layer-chromatography (TLC), Spectorphotometry, Analysis by Toxi-Lab system, immuno-assay and color tests for qualitative analysis. The tests have been adapted from standard text books and peer-reviewed journals.
   
 Following tests were found to fulfill the above criteria:
   
Plasma and RBC cholinesterase levels
in Blood samples:
Plasma cholinesterase levels are easily available. However, RBC cholinesterase is a better indicator of severity of OP poisoning. This test has been specially developed and standardized in the CEARCH laboratory.
   
Blood Lead levels by Lead Care II
Analyzer (USFDA approved)
Results available in 30 minutes
Economical
Cross checked with Atomic Absorption spectrometer
CDC and WHO recommended
   
Drug screening for drugs of abuse
(From biological samples):

This has been found to be especially useful for patients with altered sensorium and drugs like benzodiazepines. Confirmation is done with TLC and UV scanning.
Drugs detected:Amphetamine, Barbiturates, Benzodiazepines, Cocaine, Morphine, Marijuana (THC), Methamphetamine, Phencyclidine, Methadone
   
Detection by Color tests from
urine/gastric lavage samples:
These tests are done for detection of acetaminophen (paracetamol), salicylic acid, phenothiazines, imipramine, ethanol and other volatile reducing agents, phenol, thiocyanates, paraquat, Phosphorous & phosphides, mercury (G. lavage).
   
Blood paracetamol Level:
Blood levels of paracetamol are estimated after four hours of overdose to decide about the need for N-acetyl cysteine (as per Rumack-Mathew Nomogram).
   
Blood levels of salicylates,
Methemoglobin, Thiocyanate and copper:
Blood levels of these compounds are also estimated in poisoning cases.
   
Unknown drug analysis using
Toxi-Lab system:
Comprehensive:One simple screening method for polydrug specimens.
Information-rich:Features a database with extensive US and international drug photo-documentation.
Cost-effective:Low startup costs with no expensive instrument maintenance or maintenance contracts.
Environmental friendly:No spraying of reagents.
Drug analysis Using HPLC:

HPLC is considered as the 'Gold Standard' among analytical techniques.
It is used for accurate estimation of drugs useful both for Therapeutic Drug Monitoring (TDM) and drug overdose. Currently there is no immunoassay for determination of epoxide metabolite and chromatographic techniques (like HPLC) can be used.
Metabolites of certain drugs are also active as the parent compound.
(e.g. Oxcarbazepine & its mono-Hydroxy metabolite)

TDM, When?

TDM is useful in following situations:

   The drug in question has a narrow therapeutic range.

   The therapeutic effect cannot be easily assessed by clinical observation.

   Poor relationship between dose and serum drug concentrations.

   Non-linear pharmacokinetics.

   Difficulty in interpreting signs and symptoms of toxicity or therapeutic       failure or in evaluting therapeutic responses.

Antiepileptic Drugs by HPLC Phenobarbitone, Phenytoin, Carbamazepine & Its Epoxide, Oxcarbazepine & its mono-Hydroxy metabolite.
-Ethosuximide, Lamotrigine, Primidone, Sulthiame
-Lacosamide, Zonisamide, Felbamate, Rufinamide, N-Desmethylmethsuximide.
Levetiracetam.
   
Antiepileptic Drugs by HPLC Blood levels of Voriconazole, Posaconazole.
   
Antibiotics by HPLC Blood levels of Vancomycin
   
Tests under development on HPLC (i) Methotrexate from blood.
(ii) Urinary cotinine levels by HPLC
   
 

Guideline for sample collection etc:

Tests useful for the management of acute poisoning cases
Test Method Sample Turn Around Time after reaching the toxicology lab. (TAT)
    Requirement Collection Transport  
RBC Cholinesterase activity Spectrophotometry 3 ml EDTA Blood   After suspecting pesticide poisoning   2 -8℃   1 hour
Plasma Cholinesterase activity Spectrophotometry 3 ml EDTA Blood /1 ml non-hemolyzed serum   After suspecting pesticide poisoning   2 -8℃   1 hour
Blood Paracetamol level Spectrophotometry 3 ml EDTA Blood / 1 ml serum   Blood collection at least 4 hours after   ingestion; the time of ‘drug ingestion’   and  ‘blood collection’ to be mentioned   2 -8℃   2 hours
Serum Salicylate level Spectrophotometry 3 ml plain Blood   After suspecting pesticide poisoning   2 -8℃   2 hours
Blood Methemoglobin level Spectrophotometry 3 ml plain Blood   Blood collection in air tight tube/container   to prevent exposure to air   2 -8℃   1 hour
Serum/ Urine Copper Spectrophotometry 3 ml EDTA Blood / 1 ml serum   Acid washed container to be used for Urine   2 -8℃   3 hours
Serum/Plasma Thiocyanate Spectrophotometry 3 ml EDTA Blood / 1 ml serum   After suspecting poisoning   2 -8℃   3 hours
NB: The sample should be sent as early as possible for above tests

Other tests for Toxic exposures
Test Method Sample TAT
    Requirement Collection Transport  
Blood (serum) Alcohol Level Enzymatic method using Spectrophotometry 1 ml Serum/Plasma Don’t use Alcohol swab during blood collection 2 -8℃ 2 hours
Urine Color Test for Common drugs& other toxicants (Screen-1) Color test (for Salicylic Acid, Phenothiazines, Paracetamol, Imipramine & related Comps, Phenol, Paraquat,Thiocyanate) 20ml fresh Urine sample Immediately after suspecting toxic exposure 2 -8℃ 2 hours
Drug of abuse (9 drugs) in Urine (Screen-2) Strip Immunoassay 20ml fresh Urine sample Immediately after suspecting drug 2 -8℃ 1 hours
Urine drug screening (by Screen-1 & -2) Color test + Strip Immunoassay 20ml fresh Urine sample Immediately after suspecting drug 2 -8℃ 2 hours
Urine drug (26 drugs) screening (by Toxilab A) TLC (Thin Layer Chromatography) 20ml fresh Urine sample Immediately after suspecting drug 2 -8℃ 3 hours
Gastric lavage for suspected pesticides TLC 30-40 ml G. Lavage The suspected pesticide ingested by patient should be sent with G. lavage - 6 hours
Gastric lavage for drugs TLC 30-40 ml G. Lavage The suspected drug ingested by patient should be sent with G. lavage - 6 hours
Gastric lavage Color Test for Common drugs& other toxicants Mercury, Salicylic Acid, Phenothiazines, Paracetamol, Imipramine 30-40 ml G. Lavage Immediately after suspecting toxic exposure 2 -8℃ 3 hours
Blood Lead level Electrochemical 2 ml EDTA or Heparin blood Wear powder-free gloves to prevent lead contamination. 2 -8℃ 1 hours
Urine Delta-Aminolevulinic Acid (δ-ALA) Spectrophotometry 20 ml Urine Wrap Container with Aluminium foil or use to brown bottle to protect the container from light 2 -8℃ 4 hours
Urine δ-ALA and Porphobilinogen (Combined) Column chromatography & Spectrophotometry using ‘ClinRep’ kit 20 ml Urine(add this row) Wrap Container with Aluminium foil or use to brown bottle to protect the container from light 2 -8℃ 4 hours
Urine Phenol Spectrophotometry 20 ml Urine   2 -8℃ 2 hours
Detection of common Steroids in unknown drug preparation TLC (for betamethasone, dexamethasone, deflazacort, prednisolone, methyl prednisolone) Alternative medicine/powders     6 hours
NB: Above tests can be done after 2-3 days of sample collection with proper storage

Tests done on HPLC [Useful for Therapeutic Drug Monitoring and drug overdose]
Drug Test Sample Requirement TAT
Antifungal drugs Blood Voriconazole Level 1ml Separated Plasma/Serum 6 hours
Blood Voriconazole Level 1ml Separated Plasma/Serum 6 hours
Antibiotic level Blood Vancomycin Level 1ml Separated Plasma/Serum 6 hours
Antiepileptic Drugs-I Phenobarbitone, Phenytoin, Carbamazepine & its epoxide, Oxcarbazepine & its mono-Hydroxy metabolite 1 ml Separated Serum 5 hours
Other Antiepileptic Drugs-II Ethosuximide, Carbamazepine, Carbamazepine-epoxide, Ethosuximide, 10-Hydroxy-Carbamazepine, Lamotrigine, Oxcarbazepine, Phenobarbital, Phenytoin, Primidone, Sulthiame 1 ml Separated Serum 6 hours
Other Antiepileptic Drugs-III Lacosamide, Zonisamide, Felbamate, Rufinamide, N-Desmethylmethsuximide 1ml Separated Plasma/Serum 6 hours
Other Antiepileptic Drugs-IV Blood Levetiracetam 1ml Separated Plasma/Serum 6 hours
NB: (i) Blood/Serum must not be hemolyzed and Gel tubes not be used which cause interference in HPLC analysis.             Blood should be collected; serum/plasma separated as soon as possible and stored properly or transported
            at 2 -8°C.
      (ii) For trough Level of the drug, collect the sample before the next dose.
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