Clin lab test 1

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253 terms · lab tets, PFT, ABG, CXR

what can cause false results in MCV testing

Hyperglycemia, extreme leukocytosis, presence of cold or warm agglutins, extreme leukocytosis

what does an increased RDW mean

RDW = red cell distribution width is normally 11.5 - 14.5%
if high it means there is an increased variability in red cell size (anisocytosis)

WBC with dif or CBC with dif

count of white blood cells per volume of blood
normal for men and non-pregnant women: 5K-10K per cubic mm or
5.0 -10.0 x 10^9 per liter
differential part looks at composition which should be:
neutrophils 50%
band neutrophils 3-6%
lymphocytes 25-40%
monocytes 3-7%
eosinophils 0 - 3%
basophils 0 - 1%

RBC

count of number of red blood cells per volume of blood
Normals:
M should be 4.5 - 5.5 million RBCs/mcL
W should be 4.0-5.0 miliion RBCs/mcL
Children should be 3.8-6.0 million RBCs/mcL
newborns should be 4.1-6.1 million RBCs per mcL

hematocrit

measures the RBC in a given volume of whole blood
Men: 42%-52%
Women:36%-48%
Children:29%-59%
Newborns: 44%-64%

hemoglobin (Hgb)

measures amount of oxygen-carrying protein in the blood
Men: 14-17.4 grams per deciliter (g/dL)
Women: 12-16 g/dL
Children:9.5-20.5 g/dL
Newborn: 14.5-24.5 g/dL
In general, a normal hemoglobin level is about one-third the value of the hematocrit

MCV- mean corpuscular volume

measurement of the average size of your RBCs. normally 82-98 cubic millimeters

elevated when your RBCs are larger than normal (macrocytic), for example in anemia caused by vitamin B12 deficiency.

When decreased, your RBCs are smaller than normal (microcytic) as is seen in iron deficiency anemia or thalassemias.

MCH - mean corpuscular hemoglobin

calculation of the average amount of oxygen-carrying hemoglobin inside a red blood cell. normally 26-34 picograms (pg)

Macrocytic RBCs are large so tend to have a higher value, while microcytic red cells would have a lower value.

mean corpuscular hemoglobin concentration

calculation of the average concentration of hemoglobin inside a red cell. normally 32-36 grams per deciliter (g/dL)

Decreased values (hypochromia) are seen in conditions where the hemoglobin is abnormally diluted inside the red cells, such as in iron deficiency anemia and in thalassemia.

Increased values (hyperchromia) are seen in conditions where the hemoglobin is abnormally concentrated inside the red cells, such as in burn patients and hereditary spherocytosis, a relatively rare congenital disorder.

platelet count

the number of platelets in a given volume of blood. normally 140K-400K per mm^3 in adults and 150K-450K per mm^3 in chldren

Both increases and decreases can point to abnormal conditions of excess bleeding or clotting.

mpv - mean platelet volume

Mean platelet volume (MPV) is a machine-calculated measurement of the average size of your platelets. normally: 7.4-10.4 mcm^3

New platelets are larger, and an increased value occurs when increased numbers of platelets are being produced. gives information about platelet production in your bone marrow.

blood smear

looks at blood on a slide plate/smear to determine if cells are normal in shape, size, color and number

drugs that can increase WBC count

Allopurinol
Aspirin
Chloroform
Corticosteroids
Epinephrine
Heparin
Quinine
Triamterene

drugs that can lower WBC count

Antibiotics
Anticonvulsants
Antihistamines
Antithyroid drugs
Arsenicals
Barbiturates
Chemotherapy drugs
Diuretics
Sulfonamides

why would you order a WBC/
cbc

symptoms such as fatigue or weakness or has an infection, inflammation, bruising, or bleeding

leukocytosis

elevated number of white blood cells
can result from bacterial infections, inflammation, leukemia, trauma, intense exercise, or stress

leukopenia

decreased white blood cell count
can result from many different situations, such as chemotherapy, radiation therapy, or diseases of the immune system

protein, albumin, globulin (serum)
also known as total protein

determines the amount and types of protein in the blood

Normal values:
*Total protein: 6.4 - 8.3 g/dL
Albumin: 3.5 - 5.0 g/dL
Alpha-1 globulin: .1 - .3 g/dL
Alpha-2 globulin: .6 - 1 g/dL
Beta globulin: .7 - 1.2 g/dL
Gamma globulin: .7 - 1.6 g/dL
Normal A/G ratio: slightly over 1

causes of false results in total protein/albumin/globulin serum test

abnormal draw
pregnancy
drugs: estrogen, cotricosteroids, anabolic steroids, growth hormone, insulin, chlorpromazine (schizophrenia), isoniazid (TB), phenacemide (antiepileptic), salicylates, sulfonamides, tolbutamide

high total protein values are indicative of

-Chronic inflammation.
-Hepatitis B or C
-HIV.
-Possibly bone marrow disorders (multiple myeloma, Waldenstrom's Disease-polycythemia).
-High A/G ratio reflects underproduction of immunoglobulins
-Genetic deficiencies.
-Some leukemias.

low total protein values are indicative of

-Liver disorder.
-Kidney disorder.
-Malnutrition.
-Bleeding (hemorrhage).
-Extensive burns.
-Conditions that cause malabsorption (Celiac disease, Inflammatory Bowel Disease IBD).
-Low A/G ratio:
Due to overproduction of globulins
-Multiple myeloma.
-Autoimmune diseases.
Due to underproduction of albumin
-Cirrhosis
-Kidney disease (nephrotic syndrome, glomerulonephritis)

uric acid serum

looks at amount of uric acid in blood, used as screening for gout and kidney disease

Normal values: 3.4-7.0 mg/dL in adult men, 2.4-6.0 mg/dL in post menopausal women, 2.0-5.5 mg/dL in children

things that can cause false results in uric acid serum

Diets high in protein and/or foods containing purines, recent alcohol consumption, and certain medications (such as anti-inflammatory drugs or aspirin)

high uric acid serum levels indicate

hyperuricemia, gout, renal disease/failure, kidney stones, leukemia, potential precursor for hypertension, Lesch-Nyhan syndrome

low uric acid serum levels indicate

rarely seen and are not commonly considered cause for concern

BUN, creatinine (serum)

used to assess kidney function
Normal values:
BUN Values: 6-20 mg/dL
Creatinine (serum): .8-1.4 mg/dL
BUN-Creatinine ratio: 10:1-20:1

extremely high BUN creatinine serum levels can indicate

moderate to severe renal failure or other serious diseases

things that can affect BUN/creatinine serum level

medications
ingesting large amounts of protein within 24 hours prior to test

high levels of BUN in blood serum can indicate

-impaired kidney function due to acute/chronic kidney disease, damage, or failure.
-Decreased blood flow to the kidney could be another cause for an increased concentration of urea in the blood.
-congestive heart failure, gastrointestinal bleeding, hypovolema, heart attack, shock, conditions that cause obstruction of urine flow, dehydration, stress, lack of protein in diet

high levels of creatinine in blood serum can indicate

acute tubular necrosis, dehydration, diabetic nephropathy, eclampsia, glomerulonephritis, kidney failure, muscular dystrophy, preeclampsia, pyelonephritis, reduced kidney flow, rhabdomyolysis, or a urinary tract obstruction.

a high BUN:creatinine ration of >20:1 indicates

problem is located BEFORE the kidney

low levels of BUN in blood serum can indicate

severe liver disease, malnutrition, over hydration

low creatinine levels in blood serum are seen in

late stages of muscular dystrophy and in myasthenia gravis

a low BUN:creatinine ration of <10:1 indicates

a problem WITHIN the kidney

lipid profile

can also be called lipid panel or coronary risk panel
normal values
LDL: less than 100mg/dL
Total Cholesterol: less than 200mg/dL
HDL: 60mg/dL or higher in both sexes
Triglycerides: less than 150mg/dL

panic values for lipid profile

LDL: greater than 190mg/dL
Total Cholesterol: greater than 240mg/dL
HDL: less than 40mg/dL in men and less than 50mg/dL for women
Triglycerides: greater than 500mg/dL

lipid profile must be performed

after 9-12 hour fast

things that may cause false results in lipid profile

1. Eating a meal less than 8 hours before a lipid test will increase cholesterol levels.
2. Very fatty meals, such as those eaten around the holidays, can increase cholesterol levels for up to two weeks.
3. During pregnancy, women experience an increase in cholesterol levels

what high values in lipid profile can indicate

High LDL, Total Cholesterol and Triglycerides: indicate an increased risk for heart disease.
Depending on other risk factors, these high levels may require treatment.
High HDL (good cholesterol) levels show a decreased risk for heart disease.

what low values in lipid profile can indicate

Low HDL levels indicate an increased risk for heart disease.
Low LDL, Total Cholesterol and Triglycerides show a decreased risk for heart disease.

PTT (prothrombin time) / aPTT (activated partial thromboplastin time)/ INR (international normalized ratio)

blood test that determines clotting time

normals:
11-13.7 seconds(PT)
21.33 seconds (PT if pt on therapeutic thinners)
2.0 - 3.0 (INR)
2.5-3.5 (INR therapeutic level for pt on thinners)

panic value for INR and for PTT

INR >5
PTT >100 seconds

special instructions for INR/PTT testing

if pt is on anticoagulants blood draw should be done prior to the pts daily dose of anticoagulant

things that can cause false results in INR/PTT

1. Some antibiotics can increase
2. Barbiturates, oral contraceptives and hormone-replacement therapy (HRT), and vitamin K (including multivitamins and any foods with large amounts of vitamin K) can lower
3. Alcohol can lower .
4. underdrawn lab sample could also cause a false result.

low values on a PTT/INR can indicate

at risk for a blood clot and complications from blood clots (pulmonary embolism, TIA, CVA...etc.)
The patients' blood is clotting too fast and could form blood clots.

high values on a PTT/INR can indicate

patients' blood is to too thin and/or the patient's blood is not clotting in a therapeutic amount of time.
medication should be adjusted to get them at a therapeutic level

low values on RBC/hemoglobin/hematocrit can indicate

Blood loss- traumatic, post surgical,
Bone marrow suppression from drugs
Hemoglobinopathies-sickle cell, thalassemia
Nutritional deficiencies - vitamin B12, iron and folate
Cancer-colon, gastric, metastases in the bone marrow, lymphoma

high values on RBC/hemoglobin/hematocrit can indicate

Chronic obstructive pulmonary disease (COPD)
Severe burns
Congestive heart failure
Polycythemia Vera,
Kidney disease

serum electrophoresis or serum globulin electrophoresis

blood test that looks at different proteins/globulins in the blood- can also be done as a random 24-hour urine sample but that is less common

test shouldd be done after a 4 hour fast

Normal values:
•total protein: 6.4 to 8.3 g/dL (about 0.5 g/dL lower in nonambulatory patients)
•albumin: 3.5 to 5.0 g/dL
•alpha1-globulin: 0.1 to 0.3 g/dL
•alpha2-globulin: 0.6 to 1.0 g/dL
•beta-globulin: 0.7 to 1.2 g/dL
•gamma-globulin: 0.7 to 1.6 g/dL
•Serum globulin: 2.0 to 3.5 g/dL
•IgM component: 75 to 300 mg/dL
•IgG component: 650 to 1850 mg/dL
•IgA component: 90 to 350 mg/dL

things that may cause false results in serum electrophoresis

pregnancy
dehydration
burns
infection
drugs: corticosteroids, neomycin, salicylates

what high values in serum electrophoresis can mean

different proteins indicate different disease but the below are some of the options:
o Acute infection
o Heart, kidney, liver disease
o Dehydration
o Pregnancy
o Infection
o Chronic inflammatory disease (rheumatoid arthritis, systemic lupus erythematosus)
o Hyperimmunization
o Multiple myeloma
o Waldenstrom's macroglobulinemia

what low values in serum electrophoresis can mean

different proteins indicate different disease but the below are some of the options:
o Disease of immune system (lupus, rheumatoid arthritis)
o Cancer (leukemia, lymphoma, multiple myeloma
o Dehydration
o Crohn's disease
o Heart, kidney, liver, lung disease
o Infection
o Hypothyroidism
o Pregnancy
o Starvation/severe dieting
o Severe burns

bleeding time test

test is done by inflating a BP cuff and making 2 incisions on the arm below cuff- incision is blotted every 30 seconds and the time when the bleeding stops is recorded

done to determine platelet function

normal value: 8 minutes

things that can cause false results in bleeding time test

drugs: blood thinners

what can high values in bleeding time test indicate

thrombocytopenia
von Willebrand disease
Glanzmann's thrombasthenia
Bernard-Soulier syndrome
storage pool disease
fibrinogen deficiency
renal disease
dysproteinemias
vascular or platelet disorders

what can low values in bleeding time test indicate

non specified

bleeding time test reliability

not often used any more due to lack of sensitivity and specificity and it's inability to predict risks of surgical bleeding

platelet count/thrombocyte count

normal values 150,000-450,000/microliter
ordered to test for bleeding disorders or bone marrow diseases

panic values for platelet count

<20K/microliter
can cause spontaneous bleeding and is considered a life threatening risk

things that may cause false results in platelet count

number of things that can increase platelet levels:
high altitudes
strenuous exercise
being post-partum
drugs: estrogen and OCP
decrease in platelet levels can be seen in women before their menses

what do high platelet counts indicate

>400K/microliter indicates thrombocytosis

what do low platelet counts indicate

<100K/microliter or a decrease of >50% indicates thrombocytopenia

serum electrolyte normal values

Normal values:
Sodium: 136-144mEq/L;
Potassium: 3.7-5.2mEq/L in adults (3.4-4.7mEq/L in children);
Chloride: 101-111mEq/L in adults (90-110mEq/L in children);
Carbon Dioxide (Bicarbonate): 20-29mEq/L

panic values for serum electrolyte test

Sodium: <125, >160mEq/L;
Potassium: <3.0, >6.0mEq/L;
Chloride: <80, >120mEq/L;
Carbon Dioxide (Bicarbonate): <10, >40mEq/L;
Anion Gap: >30mEq/L

things that can cause false results in serum electrolyte test

potassium levels can be falsely elevated by several different specimen-collection or processing errors

what high sodium in serum electrolyte test may indicate

dehydration, Cushing's syndrome, Diabetes Insipidus, kidney disease or trauma, hyperaldosteronism

what high potassium in serum electrolyte test may indicate

damage to kidneys, severe burns, crushing injuries, heart attack, and diabetic ketoacidosis, too much acid (pH) in the blood makes potassium in the body's cells "leak" out of cells and into the blood, ACE inhibitors cause high potassium levels

what high chloride in serum electrolyte test may indicate

dehydration, too much salt in diet, kidney disease, overactive parathyroid gland

what high bicarb in serum electrolyte test may indicate

dehydration (vomiting), recent blood transfusion, overuse of medicines that contain bicarbonate (especially antacids), anorexia, chronic obstructive pulmonary disease (COPD), fluid in the lungs (pulmonary edema), heart disease, Cushing's disease, Conn's syndrome

what low sodium values in serum electrolyte test may indicate

sweating, burns, severe vomiting or diarrhea, drinking too much water, or poor nutrition; underactive adrenal glands or thyroid gland, heart failure, kidney disease, cirrhosis, cystic fibrosis, or SIADH (syndrome of inappropriate antidiuretic hormone secretion)

what low chloride values in serum electrolyte test may indicate

syndrome of inappropriate antidiuretic hormone secretion, Addison's disease, metabolic alkalosis, heart failure, ongoing vomiting

what low potassium values in serum electrolyte test may indicate

hyperaldosteronism, severe burns, cystic fibrosis, alcoholism, Cushing's syndrome, dehydration, malnutrition, vomiting, diarrhea and certain kidney diseases, such as Bartter's syndrome, diuretics cause low potassium levels

what low bicarb values in serum electrolyte test may indicate

hyperventilation, aspirin or alcohol overdose, diarrhea, dehydration, severe malnutrition, severe burns, shock, liver or kidney disease, a massive heart attack, hyperthyroidism, uncontrolled diabetes

anion gap

-a value calculated using the results of an electrolyte panel; it evaluates the difference between measured and unmeasured electrical particles (ions or electrolytes) in the fluid portion of the blood.
-the number of positive ions (cations) and negative ions (anions) should be equal. However, not all ions are routinely measured.
-this value will represent the unmeasured ions and primarily consists of anions

abnormal anion gap can indicate

certain kinds of metabolic abnormalities such as starvation, diabetes or presence of a toxic substance.

HIV ELISA and western blot test

common test for HIV testing

normal value is negative result, indicating patient's blood doesn't have HIV antibodies

how does HIV ELISA and western blot test work

1. A blood sample is obtained and sent to the lab.
2. The ELISA is used to detect HIV antibodies and a positive ELISA result is always followed by a Western blot test.
3. A positive Western blot test confirms HIV infection.
4. A negative Western blot means the initial ELISA was a false positive.
5. Western blot tests can also be inconclusive in which case further testing must be done.
- bes sure to remember the window period between infection and detection of HIV antibodies

false positives in HIV ELISA test can be caused by

Certain conditions such as syphilis, lyme disease, and lupus

false negatives in HIV ELISA test can be caused by

If a patient is tested for HIV too soon after the initial infection with HIV, a false negative may result.
This "window period" can last up to 3 months. Patients with an early HIV infection, also called an "acute" or "primary" HIV infection will often have a negative test result.

patients who should be given HIV ELISA test

- pts who ask to be tested
-pts with unusual infections seen in the immunocompromised
- pregnant women (b/c it can be passed to fetus or to baby through breast milk)
pts at high risk:
- men who have sex with men
- IV drug users and their sexual partners

serum immunoglobulin/ immunoelectrophoresis-serum test

measures the immunogloulins (antibodies) in the blood
normal values are having no monoclonal antibodies detected

panic values in serum immunoglobulin/immunoelectrophoresis-serum test

monoclonal antibodies detected in the serum sometimes may be due to certain types of cancer (multiple myeloma, chronic lymphocytic leukemia)

serum antibody tests

screen for specific antibodies in the blood
commonly screened antibodies include: HIV, HepB, H.pylori, aspergillus

normal antibodies are to have no antibodies

things that may cause false negatives in serum antibody tests

testing during the window period between infection and presence of significant amounts of antibodies

things that may cause false positives in serum antibody tests

a concurrent infectious disease

high values in serum antibody tests indicate

severity of the disease

d-dimer lab test

determines presence of thrombus, measures breakdown products of a blood clot

normally <250 ng/ml or <250 ug/L

things that may cause false positive results in d-dimer test

high levels of rheumatoid factor, bilirubin, triglycerides, and lipids
may also be higher in the elderly without being pathogenic

what high values in d-dimer test can indicate

there is abnormal fibrin degradation occurring in the body
normally plasma does not have detectable amounts of d-dimer fragments
can indicate DVT, PE

when to request a d-dimer

blood glucose/serum glucose

determines how much glucose is present in the blood, often done fasting

Normal values:
•70-99 mg/dL (3.9 to 5.5 mmol/L) is normal fasting glucose
•100-125 mg/dL (5.6 to 6.9 mmol/L) is considered impaired fasting glucose and may be predictive of diabetes.
•>126 mg/dL (7.0 mmol/L) on repeated tests indicates diabetes
•60-100mg/dL is considered within normal bounds for random capillary testing

panic values in blood glucose test

below 30mg/dL is considered severe hypoglycemia
Above 300 mg/dL is suggestive of diabetic ketoacidosis (DKA).

things that might cause false results in blood glucose test

uncalibrated glucometer
circulatory abnormalities in extremity where sample was taken
contamination of the dilution of the sample (i.e. with what was used to clean testing site)

when to order blood glucose test

signs or symptoms of hyperglycemia: polydipsia, polyuria, fatigue, blurred vision and slow healing infections
signs or symptoms of hypoglycemia: diaphoresis, polyphagia, muscle fasciculation, anxiety, altered mental status and blurred vision

high values in blood glucose test can indicate

• Diabetes
• Acromegaly
• Extremis (response to trauma, myocardial infarction or CVA/TIA )
• Chronic renal failure
• Cushing's syndrome
• Drugs: corticosteroids, tricyclic antidepressants, diuretics, epinephrine, estrogen, lithium, phenytoin, salicylates.
• Excessive food intake
• Hyperthyroidism
• Pancreatic cancer
• Pancreatitis

low values in blood glucose test can indicate

• Adrenal insfficiency
• EtOH consumption
• Drugs: acetaminophen, anabolic steroids
• Extensive liver disease
• Hypopituitarism
• Hypothyroidism
• Insulin overdose
• Insulinomas
• Starvation

homolytic complement test

often called CH50, CH100 for total or can look at different components- commonly C3, C4

Normal values:
Total blood component level (CH50): 41 to 90 hemolytic units
C1 level: 16 to 33 mg/dL
C3 levels: Male: 88 to 252 mg/dL Females: 88 to 206 mg/dL
C4 levels: Male: 12 to 72 mg/dL Female: 13 to 75 mg/dL

when is compliment test ordered

to help determine cause of unexplained inflammation
to determine if autoimmune disorder
to monitor the state of acute or chronic infections
to determine integrity of immune pathway

what high values in compliment test can indicate

certain infections
Chronic and acute inflammation
Cancer
Ulcerative colitis

what low values of CH50 in compliment test can indicate

deficiencies of C1-C9
if half the nomal value indicates a deficiency in C9
if 0 indicates deficiency in C1-C8

low values in C3 and C4 indicate

activation of classical pathways and alternate pathways

low values in compliment can indicate

Cirrhosis
Glomerulonephritis
Hereditary angioma (will also have low levels of C1 inhibitor)
Hepatitis
Kidney transplant rejection
Lupus nephritis
Malnutrition
Systemic lupus erythematosis

DAT

direct antibody test- detects RBC antibodies attached to red cells

IAT

indirect antibody test - detects unbound antibodies direced against RBC antigens other than the A and B antigens

when to perform IAT

prior to any anticipated blood transfusion and as a follow up to a transfusion reaction
part of every pregnancy work up

calcium/total calcium/ionized calcium

done to test levels of calcium in the blood

normal values:
Nonionized calcium in adults: 9.0 to 10.5 mg/dL or 2.25 to 2.75 mmol/L
Nonionized calcium in children: 7.6 to 10.8 mg/dL or 1.9 to 2.7 mmol/L
Ionized calcium in adults: 4.65 to 5.28 mg/dL

things that can cause false results for calcium serum levels

If pt has taken milk, antacid, calcium salt, or calcium supplements 8 hours before administering the test, since this will affect the test result.
Calcium values are high in children who are growing.
Calcium values are low in older men and pregnant women.

when to order calcium serum levels

screen for:
Parathyroid gland function • Kidney function • Kidney stones • Pancreatitis • Bone disease •
Find underlying cause of:
-Muscle spasms, depression, confusion, tingling around the mouth and fingers, and muscle cramping and twitching (can be caused by low calcium level in blood)
-abnormal electrocardiographic (ECG) result.
-Nausea, vomiting, bone pain, lack of appetite, weakness, abdominal pain, and constipation and increased urination (can be caused by a high calcium level in blood)

high values for calcium serum result can indicate

Hyperparathyroidism
Cancer metastasized to the bone
Kidney disease
That the patient has been on bed rest for a long period
Tuberculosis
Sarcoidosis
Addison disease
Dehydration
Hyperthyroidism
Paget disease
Chronic liver problems
Ingesting too much calcium, vitamin D, or vitamin A
Decreased phosphate blood level

what low calcium serum levels can indicate

Hypoparathyroidism
Malabsorption syndrome -Pancreatitis
Hypoalbuminemia
Low magnesium
Kidney disease
Increasing phosphate blood level

phosphorous or phosphate serum level

done to test levels of phosphorous in blood

Normal values:
Adults: 3.0 to 4.5 mg/dL or 0.97 to 1.45 mmol/L
Children: 4.5 to 6.5 mg/dL or 1.45 to 2.1 mmol/L
Children younger than 1 year of age: 4.3 to 9.3 mg/dL or 1.4 to 3 mmol/L

things that can cause false results in phorsphorous serum levels

ETOH ingestion within 12 hours prior to test
drugs ingested within 2 weeks of test: vit D, antacids, epinephrine, acetazolamide, anabolic steroids, photosphate based enemas
miscalibration of equipment

why to order phosphorous serum test

screen for bone disease, kidney disease, parathyroid gland function

what high values of phosphorous serum test can indicate

Pregnancy
Acromegaly
Hypoparathyroidism
Kidney disease
Diabetic ketoacidosis
Bone fracture that is healing
Excess vitamin D
Low level of magnesium

what low values of phosphorous serum can indicate

Osteomalacia
Malnutrition
Hyperparathyroidism
Low level of vitamin D
Liver disease
Sprue/celiac disease
Alcohol abuse
High level of calcium
Burns

phosphate and calcium have a _______ relationship

inverse

PTH, parathyroid hormone serum levels

done to determine amount of PTH in blood, usually done fasting for 10-12 hours and usually done early in the day

normal values:
10-65 picograms per mililiter pg/mL

things that may cause false results in PTH test

certain drugs can increase levels:
phosphates, anticonvulsants, steroids, isoniazid, lithium, rifampin

when to order PTH serum levels

if there is an abnormal calcium test or if pt exhibits symptoms of hypercalcemia (fatigue, nausea, abdominal pain, thirst) or hypocalcemia (abdominal pain, muscle cramps, tingling fingers)
Often ordered at intervals when someone has a disease that affects calcium regulation (parathyroid tumor) or other chronic disease (kidney disease)

what high values of PTH may indicate

Hyperplasia
Parathyroid tumor
Low calcium level in blood
Kidney disease
Pancreatic cancer
Lung cancer
Ovarian cancer
Absorption disorder of the intestines
Vitamin D deficiency

what low values of PTH may indicate

Lymphoma
Low magnesium level in blood
Excess calcium intake
Malfunctioning parathyroid gland
Multiple myeloma

rheumatoid panel/rheumatoid factor

normal value or negative titre is < 20u/mL and <1:20
negative titre indicates low probability of having RA

Rh Factor levels that are considered normal but indicate there is something going on

between 40-60u/mL or 1:80
often indicate RA

things that can cause false results in Rh factor testing

persistant viral, bacterial and parasitic infections
cancer
lung disease
liver disease
kidney disease
leukemia
multiple myeloma
TB

when to order Rh factor test

when person has symptoms or RA:
pain, warmth and stiffness in joints, it might also be ordered when evidence of the disease is noted from x-ray of the joints
to test for sjogrens

lyme titre

measure of how much of teh sample can be diluted before the antibodies to the disease can no longer be detected

normal values: less than 1:256, negative

panic value for lyme titre

greater than 1:256

false positives for lyme titre can be caused by

previous lyme infection
doesn't necessarily indicate an active infection

false negatives for lyme titre can be caused by

if tested during window between infection and accumulation of enough antibodies

when to order a lyme titre

when a patient displays symptoms of the disease and has recently been exposed
to a tick bite.
Symptoms include:
o "Bull's‐eye" rash - An expanding red rash with a pale center
o Exhaustion
o Fever
o Headache, stiff neck
o Muscle and joint pain

a thyroid or thyroid function panel usually includes which tests

looking at the amount of the following present in the blood:
Thyroid stimulating hormone
free T4 (thyroxine-unbound, active)
total T3 (triiodothyronine- bound, inactivated)
free T3 (triiodothyronine-unbound,active)

thyroid panel normal values

TSH: 0.5 to 4.7 mIU/L (milli-international units per liter)
T4: 58 - 140 nmol/L (nanomoles per liter)
FT4: 10.3 - 35 pmol/L (picomoles per liter)
T3: 0.92 - 2.78 nmol/L (nanomoles per liter)
FT3: 0.22 - 6.78 pmol/L (picomoles per liter)

when to order a thyroid panel

to assess thyroid function
when there are symptoms of thyroid dysfunction: weight gain, cold intolerance, hair loss, fatigue, increased heart rate, weight loss

what high values in the thyroid panel can indicate

hypothyroidism
(high TSH and low T3, T4)

what low values in the thyroid panel can indicate

hyperthyroidism
low TSH and high T3,T4)

what can cause inaccurate results in thyroid panel

exposure to mice (high TSH)
amiodarone (high TSH)
recent severe illness (high TSH)
glucocoriticoids, dopamine (low TSH)
old age (low TSH)
some systemic illnesses (low TSH)

joint fluid analysis or synovial fluid analysis

performed by arthrocentesis
looks at color/clarity, blood cell count, crystals and gram stain/culture of the fluid

synovial fluid analysis normal values

1. color/clarity: clear to light yellow, moderate viscocity
2. WBC's 4500-1000
3. RBCs 4.5 - 5.5 x 10^6 cells/ml male or 4.0 - 4.9 x 10^6 cells/ml female
4. crystals: non present
5. no bacteria and no organism grown in culture

when to order synovial fluid analysis

when patient has one or more swollen, read and/or painful joint
to monitor a known condition

abnormal color/clarity in synovial fluid can indicate

If red or contains red coloring then there is bleeding or an increased amount of RBC's within the joint. This could be from an injury or from a clotting disorder.
If milky white or cloudy, then there is either an increased number of WBC's due to infection or crystals associated with gout or pseudogout

abnormal blood cell counts in synovial fluid can indicate

~infection, illness, or trauma to the joint. ~if large number of neutrophils present could be a bacterial infection.
~if there are a large number (>2%) of eosinophils present, then something to keep in mind is Lyme's Disease

what crystals in synovial fluid can indicate

if MSU/uric acid can indicate gout

high concentrations of proteins found withing synovial fluid indicate

bacterial infection

decreased viscosity of synovial fluid indicates

inflammation

high levels of lactate dehydrogenase in synovial fluid can indicate

typical finding in RA and infectious arthritis

retinculocyte count

performed to assess the amount of reticulocytes in the blood at any given time

results are calculated as Reticulocyte %-#ret/#RBCx100.
Normal ranges are: Adults: 0.5% to 1.5%; Newborns: <7%; Normal values at birth: 2.5% to 6.5%.

reticulocyte counts higher than normal range can indicate

excessive bleeding, erythroblastosis fetalis(life threatening blood disorder in fetus/newborn), hemolytic anemia, or kidney disease with higher than normal erythropoietin production

reticulocyte counts lower than normal range can indicate

cirrhosis of the liver, folate,vitamin B-12, or iron deficiency, kidney disease with decreased erythropoeitin production, or a side effect from radiation therapy

ABG pH normal

7.35-7.45

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