Lead poisoning

Lead poisoning occurs when there is increased level of lead inside the body. Lead is toxic and can lead to many health problems such as headache, anemia, abdominal pain and irritability. Over time, lead poisoning can result in kidney failure, hypertension, learning difficulties, lethargy and behavioral problems. Children are at risk for lead poisoning when they are in contact with products containing lead. X-rays, blood count and CT or MRI of brain can help in identifying lead poisoning.

Lead poisoning in adults has often been traced to the use of lead based glazes on potteries and contamination of herbal medicines. Sometimes lead pipes in older homes can leach lead into water. It is safe to let the water run for a few seconds before using the water for consumption. The more time water has been sitting in the pipes, the more lead it may contain. Again hot water may contain more lead than cold water. In adults, symptoms of lead poisoning are seen when the lead level in the blood exceeds 80 µg/dL for weeks.

Lead exposure is measured in micrograms per deciliter of blood (µg/dL). The following is a guide to the standards on lead exposure set by the CDC (Centers for Disease Control and Prevention):

• 0 µg/dL : Even at birth, all people have some lead in their blood. However no level of exposure is deemed safe for children.
  
  
• 1.0 — 1.3 µg/dL : Average blood lead level among children ages 1-5 in the US
  
  
• 3.5 µg/dL : The CDC is considering using this level as a new "reference value" to identify children under age six with elevated blood lead levels. The threshold is lowered periodically to reflect new data from a national health and nutritional survey.
  
  
• 5 µg/dL : The CDC's current reference level for an elevated childhood blood level that warrants public health action, close monitoring or case management. Some 500,000 U.S. children are at or above this level, which some states define as lead poisoning.
  
  
• 10 µg/dL : Children who reach this threshold require closer attention and action to limit further lead exposure. Many states conduct inspections of the poisoned child's living environment to identify exposure sources. Research shows that a blood lead level of 10 µg/dL can lower IQ by 4 to 6 points on average.
  
  
• 45 µg/dL : Poisoning that may require hospitalization and chelation drug treatment, which helps the body to excrete lead. The drugs aren't considered effective for children with lower blood lead levels.
  
  
• >70 µg/dL: Left unchecked, acute lead poisoning can cause seizures, coma and death.
  
  

High levels of lead in the blood may require Chelation Therapy (treatment with chemical agents that bind to the heavy metal lead which can be excreted through urine). There are 4 agents :
Edetate Calcium Disodium (EDTA calcium) and Dimercaprol (BAL) are given through injections
Succimer (Chemet) and Penicillamine (Cuprimine, Depen) are taken orally.

MCV blood test

MCV (Mean Corpuscular Volume) blood test measures the size of RBC. It is a measure of the average volume of a red blood cell by dividing the hematocrit by the RBC. Any change in the size of RBC indicates certain disorders. This test is often conducted along with RDW blood test. With MCV blood test, RBCs can be categorized into normal, small or large sizes. Larger cells are usually indicative of macrocytic anemia. On the other hand, those with small cells may suffer microcytic anemia. Larger RBCs may indicate liver disease, hypothyroidism, folic acid or vitamin B12 deficiency or marrow aplasia. Decreased size of red blood cells is usually noticed in persons suffering from anemia, thalassemia, lead poisoning or chronic renal failure.

MCV Blood test range

MCV blood test is done using electrical impedance or light deflection. The MCV values are considered as significant and reliable in the clinical correlation of a disease. The standard reference value for MCV is 80-100 femolitres. The reference range varies from person to person depending on the age group. In children the reference range for MCV is given in three categories:

For Newborns (95 to 121 fl)
For Infants and Toddlers (76- 86 fl)
For Teenagers (boys: 78- 98 fl and girls 78-102fl)
For Adults 98fl

The MCV in association with underlying anemic conditions is determined by the following mathematical formulae: MCV = 10 X (packed cell volume / RBC count)

Mentzer index

Mentzer index is mathematically expressed as MCV / RBC count. The Mentzer index value determines conditions such as thalassemia when the ratio is less than 13 and it indicates iron deficiency anemia when the ratio is greater than 13.

ALT blood test

ALT blood test determines the level of the enzyme alanine transaminase (ALT) in the blood. ALT is found highly concentrated in the liver and in smaller amounts in the kidneys, heart, muscles and pancreas. This test is also called Serum glutamate and pyruvate transaminase (SGPT). Normal ALT blood levels lie between 4 - 36 units per liter (U/L) or 4-36 international units per liter (IU/L). Often this test is done along with AST blood test. ALT is measured to see if the liver is damaged or diseased. When the liver is damaged or diseased, it releases ALT in to the blood stream causing blood ALT levels to rise. An ALT blood test is often prescribed to identify liver diseases such as cirrhosis, hepatitis, jaundice and liver damage. Other causes for elevated blood ALT levels are thyroid disease, lead poisoning, polymuositis, heart attack and liver cancer.