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Nurses' and Nursing Students' Guide to Doing aGeneral Overview of Labs ValuesUnderstanding Plain and Simple What Lab Values Mean for Your Patient

Many times students are overwhelmed looking at a cumulative lab report, wondering what does it all

mean and what is important. Often lab tests are integrated with various disease processes

throughout the curriculum and therefore you look at one or two values at a time not looking at the

big picture and how values are related. From the very beginning of your clinical experience you

should evaluate lab values as part of your assessment of the patient. To do a general overview look at

the groups of labs for abnormalities, if there are none that's good and move on, but if there are

abnormalities in that group you will have an idea of what to be concerned about. Discuss with your

instructor, primary nurse, and the physician. Medicine is very specialized these days; sometimes the

Cardiologist overlooks the UA results.

Look at important groups of chemistries:

Electrolytes-Think electrical activity! Electrical activity in the human body includes important

items such as nerve impulse transmission and depolarization / repolarization of muscles (including

the heart). Disturbances can effect mental status, induce seizures, induce cardiac dysrhythmias,

change the effect of antidyrsrhythmic drugs, cause muscle excitation or weakness. (Look at

Potassium, Sodium, Chloride, Calcium, Magnesium)

Indicators of Renal Function-Kidney function is vital and somewhat tenuous in the elderly

population. The kidneys remove waste products from the body and in some cases excrete drugs.

Delayed drug excretion could lead to toxicity. Monitor renal function (Look at Creatinine and

BUN)carefully, especially if your patient is undergoing any procedures using contrast dye. Any x-ray

exam ending in "ography" tend to use contrast medium that is hard on the kidneys, such as

angiography. Protein in the urine also indicates kidney problems.

Indicators ofDiabetes-Diabetes is a risk factor for cardiovascular, kidney (look at indicators of

renal function), and other disease processes. Identifying the presence of diabetes (Look at

Glucose), or the effectiveness of treatment (Look at Hgb A1C) is vital. Hemaglobin A1C gives an

indication of average blood sugars for the past 3 months. If a diabetic patient is under good control

blood sugars should be in the normal range. Spikes in blood sugars are seen withinfections(Check

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WBC), changes in patient behaviors (might indicate neurological changes such as a patient admitted

with high blood sugar because they are eating inappropriately due to advancing dementia)

Indicators of Liver Function-Another important organ for the removal of wastes and drugs.

Liver enzymes (Look at ALT, AST, GGT, LDH) are usually inside the cell, they are elevated when

there is cell damage/death and the enzymes escape increasing levels in the blood stream. Waste

products (Look at Ammonia, Bilirubin) accumulate if the liver is not functioning well. Many

plasma proteins are manufactured by the liver (Look at Albumin) as well at clotting factors (Look

at PT / INR) which can lead to problems with fluid dynamics and coagulation. The liver is the

major organ for drug biotransformation. This is the change drugs go through which either degrades

or activates the drug. If the liver function is poor either the drug will accumulate or in the case of

pro-drugs won't be transformed into a substance usable by the body(Look at drug levels).

Lab tests for Cardiovascular Disease-Cardiac enzymes should be mainly inside the cell and

increase in the blood stream when cell damage / death occurs (Look at CK,

Troponin). Elevated cholesterollevels are a risk factor for CV disease (Look at Total

Cholesterol, HDL, LDL, Triglycerides). Another lab that may indicate risk for CV disease and

helps in the diagnosis of congestive heart failure isBNP (B-type natriuretic peptide)

Coagulation Studies-these look at the ability to clot (PTT, PT / INR). Elevations indicate the

patient has a greater chance of bleeding. Also look at platelets. If bleeding is occurring they will get

used up or if a patient has decreased platelets for other reasons in combination with elevations of

coagulation studies there is a greater risk of bleeding. Deep vein thrombosis and pulmonary embolus

are examples of problems caused by the presence of undesirable clots (Look at D-Dimer).

Labs Indicating Inflammation-more and more inflammation has been found to play a role in

major disease processes. ESR(Erythrocyte Sedimentation Rate) is a general indicator of infection

that corresponds with the amount of inflammation. CRP (C-reactive protein) is an abnormal protein

produced during acute inflammatory processes. It increases earlier than ESR and increases are seenwhen there is necrotic tissue (example myocardial infarct) in the body or infection.

Look at the CBC (complete blood count)

Labs related to Oxygenation-RBC's are responsible for oxygenation. Decreased RBC's equals

decreased oxygen carrying capacity. This can result in fatigue, shortness of breath, and decreased

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healing. Because of their color, decreased cells can result in pallor. Red cells are by far the cell type of

the greatest number in the blood. Increased levels increase blood viscosity, micro-infarcts and

hypertension.(Look at RBC, HGB, HCT) Characteristics (size, weight, color, range of cell sizes) of

the red cells are measured by indices (Look for MCV, MCH, MCHC, RDW). Increased numbers

of immature red cells (Look for Reticulocyte Count) indicates increased red cell production

which depending on the etiology could be a good (example: positive response to anemia treatment)

or bad thing (polycythemia vera).

Labs related to Immune Function-WBC's are the backbone of the immune system. Increases

indicate the presence of infection while decreases indicate the inability to fight infection. Alterations

high or low can also occur with leukemias. In this malignant disease process what ever the amount of

white cells present there is still an increased risk of infection. The Differential is a breakdown by

percentage of the white cell types. Elevation in particular types can infer a type of infection

(examples: elevated Neutrophils, bacterial infection, increased Lymphocytes, viral infection)

Labs related to clotting-Platelets are the cell component of clots. Decreased levels may result in

bleeding (check RBC, HGB, HCT) or be a result of bleeding (Platelets get used up trying to stop

bleeding by forming clots). Increased levels may result in unwanted clots. Platelets are attracted by

and become more likely to aggregate by the presence of inflammation (Check for labs indicating

inflammation).

Urinalysis: The urinary tract is a common site for infections and a major cause of sepsis in the

elderly and disabled.