Wednesday, January 23, 2013

How long can blood stay in a tube before being tested for blood alcohol level?

Q. Blood was drawn into a test tube but lab is closed and can't be tested until tomorrow. Will it still be accurate?

A. You have 14 days per below:

__________________________________
Whole blood or serum

Volume: 7 mL

Minimum Volume: 0.5 mL

Container: Gray-top (sodium fluoride) tube (preferred) or red-top tube. Submit original unopened tube.

Special Instructions: Do not prepare venipuncture site with alcohol or remove stopper from tube.

Storage Instructions: Refrigerate

Stability: Temperature Period
Room temperature 14 days
Refrigerated 14 days
Frozen 14 days
Freeze/thaw cycles Stable x3

Reference Interval: Negative (cutoff = 0.010%)

Use: Quantitation of alcohol level for medical or legal purposes; test unconscious patients; used to diagnose alcohol intoxication and determine appropriate therapy; detect alcoholism and to monitor ethanol treatment for methanol intoxication. Must be tested as possible cause of coma of unknown etiology since alcohol intoxication may mimic diabetic coma, cerebral trauma, and drug overdose.

Methodology: Gas chromatography (GC)

Additional Information: Ethanol is absorbed rapidly from the GI tract. Peak blood levels usually occur within 40 to 70 minutes on an empty stomach. Food in the stomach can decrease the absorption of alcohol. Ethanol is metabolized by the liver to acetaldehyde. Once peak blood ethanol levels are reached, disappearance is linear; a 70 kg man metabolizes 7-10 g of alcohol/hour (15±5 mg/dL/hour). The urine:blood ratio is considered to be about 1.35:1 but is quite variable. The average saliva:blood ratio is 1:20. Symptoms of intoxication in the presence of low alcohol levels could indicate a serious acute medical problem requiring immediate attention. The half-lives and effectiveness of certain drugs (eg, barbiturates, etc) are increased in the presence of ethanol.


18. What is �blood typing�? How is it done? Why is it so important to run blood typing before a blood transfus?
Q. 18. What is �blood typing�? How is it done? Why is it so important to run blood typing before a blood transfusion? What happens if mom and baby have different blood types?

A. Blood typing is determining the antigens present on a red blood cell.

In a clinical setting, blood type is determined by mixing red blood cells with in three different tubes. One with anti-A antibodies, one with anti-B antibodies, and another with anti-D antibodies. This determines the forward type. The person's plasma (the liquid portion of blood) is mixed in two other tubes, one with type A red blood cells, and the other with type B red blood cells to determine the reverse or back type. Agglutination (red cells clumping) indicates a reaction between antigen and antibody. So if there is agglutination in the tubes of anti-A, anti-D, and B red blood cells, the person is A+.

It is important to determine the blood type because of the antibodies that are present to ABO blood group antigens that are not present on the person's red blood cells. For example, type A individuals are expected to produce anti-B antibodies. If you transfuse blood that has one of the antigens that the body has made antibodies toward, the antibodies will attach to the transfused red blood cells and hemolyze them. The resulting reaction can cause death.

If mom and baby have different blood types there is a chance that the mom's antibodies cross the placenta and start destroying the baby's red blood cells. In mild cases it will cause increased bilirubin levels after birth. In severe cases it could cause death of the baby if there is no intervention. ABO incompatibilities between mother and baby rarely cause major problems.


What should purified blood contain after being filtered in the kidneys?
Q. when blood is filtered in the kidney and then back in the renal vein, what should that blood contain?

A. Blood proteins. They are too large to filter through the fenstrated endothelium of of glomerulus in the kidney nephrons.



EDIT: In addition the blood will contain hemoglobin and anything else that is the same size or larger than a red blood cell.


What kind of blood is given in a transfusion to these 3 patients?
Q. What kind of blood is given in a transfusion to these 3 patients?
Rh-
AB
A+

What type of blood is given to these 3 blood types if they needed a blood transfusion?

A. Blood types such as A+ summarise two different typing systems: ABO (A, B, AB, O) and Rhesus (positive and negative). The two work in similar ways but aren't connected.

In each case the types are determined by whether or not you have a bit of chemical on your blood cells. These 'antigens' can be called A, B and Rh. If you don't have one, you're likely to have antibodies against it. If your blood cells have all three, you're AB+ (short for AB type & Rhesus+), if none you're O-.

So to use that for your questions:

Rh-
This isn't a whole blood type, just the Rh factor without the ABO type. You might give someone with Rh- a negative type, possibly AB-, A- or B- depending on their ABO type. If you didn't know (or you knew they were O-) you'd give them O- as O- is the universal donor (or as close a you get to one - you have to ignore plasma and rare blood types and stuff)

AB
This isn't a whole blood type either. You could give them any ABO type in theory as AB is the universal acceptor (or as close as you get to one... blah-de-blah). If you didn't know whether they were AB+ or AB-, you'd give them AB-, or failing that another negative type.

A+
You'd give them A+, or failing that O+, or failing that O-, but _nothing_else_.





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