VENTURE 17             - Private Education for the Medical Arts and Sciences

COMMON LABORATORY VALUES



CHEMISTRY


Troponin:

  • Troponin I : less than 10 µg/L
  • Troponin T : 0–0.1 µg/L

Normal troponin levels 12 hours after chest pain has started mean a heart attack is unlikely.

Albumin: 3.2 - 5 g/dl

Alanine Aminotransferase (ALT), SGPT: <35 IU/L

Aspartate Aminotransferase (AST), SGOT: < 35 IU/L  (20-48)

Alkaline phosphatase: Adults: 25-60: 33 - 131 IU/L; Adults > 61 yo: 51 - 153 IU/L

Ammonia: 20 - 70 mcg/dl

Bilirubin, direct: 0 - 0.3 mg/dl

Bilirubin, total: 0.1 - 1.2 mg/dl


Creatine kinase (CK) and isoenzymes

CK-BB: 0%

CK-MB (cardiac): 0 - 3.9% (Most doctors use the magic number, 6%)

CK-MM: 96 - 100%

Total CK: 8 - 150 IU/L


Electrolytes and Renal Profile

Calcium: 8.8 - 10.3 mg/dL; Calcium, ionized: 2.24 - 2.46 meq/L

Chloride: 95 - 107 mEq/L

Magnesium: 1.6 - 2.4 mEq/L

Phosphate: 2.5 - 4.5 mg/dL

Potassium: 3.5 - 5.2 mEq/L

Sodium: 135 - 147 mEq/L

Blood Urea Nitrogen: 7 - 20 mg/dl

Creatinine (mg/dl): 0.5 - 1.4

Glucose, fasting (mg/dl): 60 - 110

Glucose, (2 hours postprandial), (mg/dl): Up to 140

Hemoglobin A1c, % (as a screening test)

5.4 = Normal


5.5-6.4 = High risk/pre-diabetic; requires screening by glucose criteria


6.5 = Diabetes, confirmed by repeating the test on a different day.


In general, therapy should target an A1C level of 6.5% or less for most non-pregnant adults.


Iron (mcg/dl): 65 - 150

Total Iron Binding Capacity (TIBC): 250 - 420  mcg/dl

Transferrin: > 200 mg/dl

Lactic Acid (meq/L): 0.7 - 2.1

Lactic Dehydrogenase (LDH), Total: 56 - 194 IU/L

Osmolality: 289 - 308 mOsm/kg


Uric Acid: (male): 2.0 - 8.0 mg/dl

                      (female): 2.0 - 7.5 mg/dl


Lipoproteins and triglycerides

Cholesterol, total: < 200 mg/dL

HDL Cholesterol: 35 mg/dL.  Negative risk factor: 60 mg/dL

LDL Cholesterol: 65 - 180 mg/dL

Triglycerides: Normal: < 150 mg/dL

                              Borderline-high: 150 to 199 mg/dL

                              High: 200 to 499 mg/dL

                              Very High: >499 mg/dL


Thyroid Function Tests(Normal Ranges)

Thyroid Stimulating Hormone (TSH): 0.5 - 4.70 µIU/mL

American Association of Clinical Endocrinologists guidelines changed the normal range for TSH to: 0.3 - 3.04 mIU/L.

Thyroid Releasing Factor (TRH): 5 -25 mIu/mL

Total T4 (TT4) bound and free T4: 4.5 -11.5 ug/dL

Free T4(FT4), free T4: 0.8 -2.8 ng/dL

Free T4 Index (FT4I), estimate of free T4, FT4I = TT4 x RT3U = 1.0 -4.3 U

Total T3 (TT3), bound and free T3: 75 -200 ng/dL

Resin T3 Uptake (RT3U), binding capacity of TBG: 25 -35%

Thyroglobulin: 5-25 ng/mL

Radioactive Iodine Uptake (RAIU) Distribution of radiolabeled iodine in the thyroid: 5 hr = 5 to 15%; 24 hr = 15 to 35%

Notes regarding thyroid tests:

TSH: best measure to determine thyroid function.

Free T4: much more useful then total T4 (e.g. interested in unbound or active form). Total T4

                  not commonly measured. Greatly affected by TBG. 

Free T4 index
: indirect measure of free T4. Corrects for high/low values of TBG.

Total T3
: not as useful as free T3, however, may be useful in locating problems with TBG, or if

                    looking for problems with peripheral conversion of T4 to T3. 

Resin T3 Uptake
: if low, then TBG binding capacity is high. Opposite if T3 uptake is high.

Thyroglobulin
: nonspecific test that is elevated when the thyroid gland is inflamed or

                                enlarged.


ARTERIAL BLOOD GASES                                            

pH: 7.35 - 7.45

pCO: 35 - 45

pO: 70 - 100

HCO: 19 - 25

O: Sat %: 90 - 95


HEMATOLOGY


Complete blood count (CBC) Adults (Male/Female)

Hemoglobin (g/dl): 13.5 - 16.5/12.0 - 15.0

Hematocrit (%): 41 - 50/36 - 44

RBC's ( x 10/ml): 4.5 - 5.5/4.0 - 4.9

RDW (RBC distribution width): <14.5                                      

MCV: 80 - 100

MCH: 26 - 34

MCHC %: 31 - 37

Platelet Count: 100,000 to 450,000


WBC Differential:

WBC (cells/ml): 4,500 - 10,000

Segmented neutrophils: 54 - 62%

Band forms: 3 - 5% (above 8% indicates left shift)    

Basophils: 0 - 1 (0 - 0.75%)

Eosinophils: 0 - 3 (1 - 3%)

lymphocytes: 24 - 44 (25 - 33%)

Monocytes: 3 - 6 (3 - 7%)

Neutrophils (aka polymorphonuclear cells, PMNs, granulocytes, segmented neutrophils, or segs) fight against infection and represent a subset of the white blood count.  


The Absolute Neutrophil Count (ANC), refers to the total number of neutrophil granulocytes present in the blood. Neutropenia by definition is an ANC below 1800/mm3 (some sources use a lower value).


Neutropenia: High risk of infection. Remember that a reduced WBC is known as leukopenia.

Normal value: >1800 cells/mm3.

Mild neutropenia: 1000 - <1800/mm3.

Moderate neutropenia: 500 - <1000/mm3.

Severe neutropenia: < 500/mm3.


URINALYSIS

Normal values:

Appearance: straw or yellow colored / clear

Specific gravity: infant: 1.002 - 1.006, child and adult: 1.001 - 1.035

pH: Child and adult: 4.6 - 8

Following substances should be negative: acetone, bilirubin, blood, glucose, nitrite, protein, leukocyte esterase.

WBC: 0 - 4/HPF

RBC: Male: 0 - 3/HPF    female: 0 - 5/HPF

Epithelial cells: Occasional

Hyaline casts: Occasional

Bacteria: None

Differential diagnosis:

Bilirubin Positive: hepatitis, obstructive jaundice

Blood Positive: tumors, infection, trauma, hemolytic anemia, coagulopathy, interstitial nephritis, polycystic kidneys, kidney stones, burns, cystitis, prostatitis, pyelonephritis.

Epithelial cells Positive: acute tubular necrosis, necrotizing papillitis

Glucose Positive: diabetes, cushing's disease, burns, steroids, hyperthyroidism, pancreatitis, pancreatic carcinoma, shock

Ketones Positive: diarrhea, vomiting, DKA, starvation, high fat diet, hyperthyroidism, pregnancy, febrile states.

Leukocyte Esterase (detects 5 or > WBC). Used along with test for nitrites to detect UTI (predictive capacity: approximately 74 %).  If both nitrites and leukocyte esterase are negative, there is a 97% chance that a UTI is not present.

NitritePositive: Infection present. Nitrates are converted to nitrites by many strains of bacteria.

Protein Positive: glomerulonephritis, pyelonephritis, nephrotic syndrome, pre-eclampsia, malignancies, heavy exercise, stress, CHF, malignant hypertension

Normal urine output: (minimum): 0.5 to 1 ml/kg/hr daily

Oliguria: < 500 ml urine/ 24 hours

Anuria: < 100 ml urine/ 24 hours.

Low urine output potential causes:

Prerenal: heart failure, shock, volume depletion, third spacing fluids, renal artery compromise

Renal: acute tubular necrosis, end-stage renal disease, interstitial disease, glomerular disease,
drug induced (Aminoglycosides, amphotericin B, cisplatin, colistin, cyclosporin, dextran, gallium, hydroxyurea, lithium, methicillin, methotrexate, methoxyflurane, nitrofurantoin, pentamidime, plicamycin, streptozocin, and vancomycin.),  bilateral cortical necrosis

Post-renal: neurogenic bladder, obstruction of ureter, bladder neck, or urethra.


Differential diagnosis Lab findings regarding low output:

pre-renal/renal:

Urine/serum creatinine >40 /<20

fractional excreted sodium: [UNa/serum Na] / [Ucr/ serum creatinine] x 100 <1/>1

Urine osmolality: >500/<350

Urinary sodium <20/>40