hCG -HUMAN CHORIONIC GONADOTROPIC HORMONE

hCG is the hormone being detected in most pregnancy tests. It is normally produced by the placenta during pregnancy and is also markedly elevated in pathologic conditions like seminoma, hydatidiform mole and teratoma, among others.

TOXICOLOGY

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Divisions of Toxicology

1. Emergency - deals with overdosage of drugs
2. Drug Abuse Screening- deals with substances of abuse
3. Therapeutic Drug Monitoring - deals with drugs for therapeutic use
4. Forensic - deals with the medical -legal aspect
5. Industrial - deals with industrial products.

EMERGENCY TOXICOLOGY

SALICYLATE poisoning - is the most common cause of ET in children.
Salicylate/acetysalicylate - the active component of aspirin.

DRUG ABUSE SCREENING

Most common substances of abuse are cigarette and alcohol.

THERAPEUTIC DRUG MONITORING

The purpose of this is to establish the optimum concentration of the drug that could cure the patient.

FORENSIC

Prohibited drugs are usually involved in this.

INDUSTRIAL

pesticides and insecticides are the most common substances involved.

BLOOD GAS ANALYSIS OUTLINE

The determination of blood gas is considered a special test in the local setting.
pCO2, pH and HCO3 are usually assayed. The results help in the evaluation whether a patient has acidosis or alkalosis.

Conditions:

Values : pH - decreased , PCO2 normal, HCO3 - decreased
Condition - metabolic acidosis
Compensatory mechanism - hyperventilation , increase excretion of CO2
decreased retention of CO2

Values: pH increased, HCO3 - increased , PCO2-normal
Condition - metabolic alkalosis
Compensatory mechanism - hypoventilation, decreased excretion of CO2
increased retention of CO2

Values : pH- increased , PCO2 - decreased , HCO3 -normal
Condition - respiratory alkalosis
Compensatory mechanism : increased retention of HCO3
decreased excretion of H+

Values: pH-decreased , PCO2 -increased, HCO3 -normal
Condition: respiratory acidosis
Compensatory mechanism : increased retention of HCO3,
increased excretion of H+

Henderson=Hasselbalch Equation: (H & H)


pH = 6.1 + log (HCO3)/DCO2

HCO = TCO2-DCO2

DCO2 = PCO2 X 0.031


Where: pH =indicates the acidity or alkalinity of a solution (hydrogen ion concentration.
HCO3 - bicarbonate
DCO2 - dissolved carbon dioxide
TCO2 - total carbon dioxide

Sample Problems:

Based on the following lab results obtained,
1. What is the acid base status of the patient?
2. What further test would you recommend?
3. What may be the possible causes of the condition?
4. Show all computations.

laboratory data:

TCO2 = 20 mmol/L
PCO2 = 30 mmHg

For more on blood gas analysis, visit the site below:

labtests on line

TURBIDIMETRY

Turbidimetry measures the amount of light blocked by particles in a solution. The amount of light blocked is dependent upon its cross sectional area, its size and amount in the unknown solution. For more information click the link below:

Turbidimetry

ELECTROPHORESIS

Migration of charged particles or solutes in an electric field. The net charge of the molecule, their size and shape, the strength of the electric field and the support medium used, influence the rate and speed of distribution of the unknown particles.

'Electrophoresis' link';

Image from: http://en.wikipedia.org/?title=Gel_electrophoresis

EMISSION FLAME PHOTOMETRY (EFP)

• This method measures the concentration of an unknown solution by measuring the emitted flame from these solutions. Metal salts (Li,K,Na) are usually measured making use Of this method.



Image from this site, enter the LINK below for more information:

'Emission Flame Photometry! link';
Image from http://www.resonancepub.com/images/section701.gif

NEPHELOMETRY

Image from: http://www.lib.mcg.edu/.../ch4/ch4img/nephelom.jpg
and http://www.gmi-inc.com/CliniLab/Beckman%20Immage.htm

Enter the LINK below to know more:

'Nephelometry' link';

NEPHELOMETRY

The light that is scattered by particles in the unknown solution is measured and made as a basis of determining its concentration.

Factors affecting the amount of light scattered are:

a.the wavelength used – dispersion of light is inversely proportional to the
wavelength.
b.the size of the particles
c.the amount of particles in solution
d.the cross sectional area of the particles
e.the source of light - monochromatic lights give more reliable readings because they
minimize sample heating and have more stable readings.

FLUOROMETRY

This method measures the fluorescence of substances in solution and make this as a basis of determining the unknown concentration. This is done by measuring the electromagnetic radiation absorption of excited atoms when they return to a higher energy level than their original levels. The wavelength used will be longer to the excitation wavelength.

Parts of a basic filter fluorometer:

1. Energy Source
2. Primary filter
3. cell or Sample holder
4. Attenuator
5. Secondary filter
6. Detector (Photomultiplier)
7. Readout

ENYZMOLOGY

The pancreatic enzymes:

1. lipase
2. amylase

The hepatic enzymes (TRANSCRIBE)

1. 5 nucleotidase
2. ALP
3. ALT
4. LAP
5. GGT
6. LDH
7. OCT
8. CHS - the only enzyme decreased in liver disease


Cardiac Enzymes (TRANSCRIBE)

1. CPK
2. AST
3. LDH