How To Interpret Your Lab Tests

How To Interpret Your Lab Tests
Presentation by: Janice Price, M.Ed, RN
Swedish Medical Center


TESTS

* CBC: Complete Blood Count
* Serum Chemistries
* Liver Function/ Amylase
* Lipids: Blood Fats
* Immune System: CD4 & Viral Load

CBC: Complete Blood Count

* Red Blood Cells: RBC
* White Blood Cells:WBC
* Platelets: Plts
* Serum/Plasma

Blood Cell Types
Bone Marrow

* All Blood Cells made in bone marrow.
* Bone Marrow is the spongy centers of bones sometimes seen in cuts of meat

Stem Cells

* Stem cells are young cells
* All blood cells start as stem cells
* They get “drafted” as RBCs, WBCs or platelets depending on the body’s needs

Red Blood Cells

* Called erythrocytes
* “cytes” = cells
* Shaped like bagel with hole covered over
* Filled with hemoglobin that carries oxygen from the lungs to every cell in the body.

White Blood Cells

* WBCs are disease fighters
* Some make antibodies and some fight invaders directly
* Divided into categories depending on function and what they look like.

Types of White Cells

* Lymphocytes: B and T cells. Agranulocytes
* Granulocytes: polymorphonucleocoytes mostly neutrophils
* Monocytes: mature into macrophages (big eaters)

A macrophage attacking a bacteria with
a cellular extension called a pseudopod

Abbreviations

* RBC = Red Blood Cell
* WBC = White Blood Cell
* HCT = Hematocrit
* Hbg = Hemoglobin
* ANC = Absolute Neutrophil Count

TESTS OF IMMUNE FUNCTION

A human cell infected with a rhinovirus ruptures,
relasing millions of new viruses

A human T-helper cell is under
attack by HIV virus

Viral Load Tests

* PCR: Most common. Usually expressed has HIV-1 PCR in copies per milliliter. Roche Amplicor
* bDNA: values are different. Usually ½ of PCR value
* NASBA: nucleic acid sequence based amplification. Values are also different

UNDETECTABLE VIRAL LOAD DOES NOT MEAN NO VIRUS PRESENT

Remember: there are other places for virus to hide
Viral Load Expressed as Log
10 x = viral load

Genotype/Phenotype

Blood Types
Red Blood Cells: The Oxygen Carriers
T Killer cells attacking a cancer cell
White Blood Cells: Infection Fighters
Lymphocytes
Granulocytes
Neutrophils
Eosinophils
Basophils
Monocytes

Platelets: For Blood Clotting

Liver Function Tests (LFTs): LFTs include a number of markers that help determine liver status. These include ALT (SGPT), AST (SGOT), LDH, alkaline phosphatase and total bilirubin. Elevated liver enzymes are commonly caused by certain medications. Elevated enzyme levels can also be caused by liver disease such as hepatitis B or C, injuries, and tumors. Abnormal liver function test levels are common in 60-70% of people with HIV, but liver failure is unusual. High alkaline phosphatase levels along with normal bilirubin levels can show serious disease and are often seen in people with Mycobacterium avium Complex (MAC), cytomegalovirus (CMV), histoplasmosis, drug side effects or Kaposi's Sarcoma. Bilirubin, a product of dead red blood cells, is eliminated through the liver. High bilirubin levels in the blood can indicate hepatitis (associated with a yellow skin color), bile duct obstruction and other liver problems.

T-Cells train in Thymus. Involved in cell-mediated immunity: basically, hand-to-hand combat.
Many kinds: CD34, CD38, etc

Two of interest: CD4 and CD8 In HIV CD4 goes down and CD8 goes up.
* Nl CD4 about 600-1200/mm3.
* 2. Function important, but can’t tell from #’s
* 3. CD4 at type of lymphocyte. Absolute vs %
* Daily, hourly fluctuation.
* CD4:CD8 normally 2:1. Reverses in HIV as probable compensation.
* CD4 count usually lags behind VL, but good indicator of when to start treatment


Vaccines, illnesses, flare-ups of other viral illnesses like herpes
Test is sensitive to 0.5 log. Log is the power of 10 that will give you the VL

There are four basic blood types:

* Type A with A antigen on the red cells and anti-B antibodies in the plasma.
* Type B with B antigen on the red cells and anti-A antibodies in the plasma.
* Type AB with both A and B antigens on the red cells and neither anti-A nor anti-B in the plasma.
* Type O with no A or B antigens on the red cells and both anti-A and anti-B antibodies in the plasma.

If you are a Type A person, you do not carry antibodies against A markers. But you do have antibodies against Type B blood.
If you are a Type B person, you have antibodies against Type A cells.
If you are a Type O, you have antibodies against both Type A and B!

How To Interpret Your Lab Tests.ppt