Diagnostic Laboratory Study Guide

Complete Metabolic Panel (CMP)

A comprehensive blood test that measures various substances in the blood to assess metabolic function.

Glucose (Glu)

Normal value: 70-110 mg/dL

Calcium (Ca)

Normal value: 8.8-10.4 mg/dL (total); Ionized: 4.65-5.28 mg/dL

Sodium (Na⁺)

Normal value: 135-145 mEq/L

Potassium (K⁺)

Normal value: 3.5-5.0 mEq/L

Bicarbonate (HCO₃⁻)

Normal value: 22-28 mEq/L

Chloride (Cl⁻)

Normal value: 96-106 mEq/L

Blood Urea Nitrogen (BUN)

Normal value: 6-20 mg/dL

Creatinine (Cr)

Male: 0.9-1.3 mg/dL; Female: 0.6-1.1 mg/dL

Albumin (Alb)

Normal value: 3.5-5.2 g/dL

Total Protein (TP)

Normal value: 6.0-8.3 g/dL

Alkaline phosphatase (ALP)

Normal value: 52-142 U/L

Alanine aminotransferase (ALT)

Normal value: 4-35 U/L

Aspartate aminotransferase (AST)

Normal value: 0-35 U/L

Complete Blood Count (CBC)

A blood test that evaluates overall health and detects a variety of disorders.

White blood cell (WBC)

Normal value: 4,500-10,500 /mm³

Red blood cell (RBC)

Male: 4.2-5.4 million/mm³; Female: 3.6-5.0 million/mm³

Hemoglobin (Hgb)

Male: 14-17.4 g/dL; Female: 12-16 g/dL

Hematocrit (Hct)

Male: 42-52%; Female: 36-48%

Platelets (Plt)

Normal value: 140,000-400,000 /mm³

Hemoglobin A1c (HbA1c)

Normal value: 4-6% (goal for diabetics <7%)

Leukocytosis

Elevated WBC above 10,500/mm³, indicating possible infection or inflammation.

Anemia

Decreased oxygen-carrying capacity of the blood, often indicated by low RBC, Hct, and Hgb levels.

Platelet count < 50,000/mm³

Indicates thrombocytopenia, which is a condition where the platelet count is below the normal range of 140,000-400,000/mm³.

Major function of platelets

Platelets are responsible for blood clotting (hemostasis) and aggregate at injury sites to form a temporary plug and activate the clotting cascade.

Thrombocytopenia

A condition characterized by a platelet count < 150,000/mm³, severe when <50,000, and critical when <20,000.

Signs of thrombocytopenia

Bruising (ecchymosis), petechiae, nosebleeds (epistaxis), bleeding gums, hematuria, GI bleeding, prolonged bleeding from cuts, and heavy menstrual bleeding.

Nursing care for low platelet count

Monitor closely for any bleeding, avoid invasive procedures, institute fall precautions, educate patient on avoiding aspirin/NSAIDs, monitor CBC trends, and report abnormal findings promptly.

Major concern for platelet count <50,000/mm³

Risk for bleeding, both external and internal, with even minor trauma potentially causing serious blood loss.

Major concern if platelet count drops to <20,000/mm³

Life-threatening risk for spontaneous bleeding, especially intracranial hemorrhage, requiring strict bleeding precautions and frequent neuro checks.

Urinalysis - Dark amber color

Suggests dehydration or concentrated urine.

Urinalysis - Cloudy clarity

May indicate infection (UTI), presence of WBCs, bacteria, or crystals.

Urinalysis - pH 8.0

Borderline high; alkaline urine may be seen with UTI, certain diets, or after meals.

Urinalysis - Specific gravity 1.050

Abnormally high; suggests very concentrated urine, dehydration, or possible glycosuria/proteinuria.

Nursing care for abnormal urinalysis

Encourage oral fluids unless contraindicated, monitor for signs of infection, and ensure proper specimen collection to rule out contamination.

Signs of infection to monitor

Fever, dysuria, frequency, urgency, and foul-smelling urine.

Platelets = 'Plug & Protect'

A summary phrase indicating the primary function of platelets in hemostasis.

<50,000 = bleeding risk

Indicates a significant risk for bleeding complications.

<20,000 = spontaneous bleeding

Represents an emergency situation due to the high risk of spontaneous bleeding.

Abnormal Urinalysis

Report promptly for possible culture & sensitivity, antibiotics if needed.

Patient Education

Teach about hydration, hygiene, and reporting symptoms of UTI.

Dark + Cloudy + Concentrated Urine

Indicates dehydration or UTI.

Nursing Care Actions

Hydrate, Monitor, Report, Educate.

Hydration Management

Encourage increased oral fluids (unless contraindicated) to help dilute urine and flush bacteria.

Infection Monitoring

Assess for signs of UTI: burning with urination, frequency, urgency, suprapubic pain, fever, foul-smelling urine.

Urine Culture and Sensitivity

Prepare to confirm infection and guide antibiotic therapy.

Perineal Hygiene

Reinforce good perineal hygiene.

Safety & Comfort

Educate patient to report dysuria, back/flank pain, or fever promptly.

Comfort Measures

Provide perineal care and frequent toileting access.

Collaborative Care

Report abnormal findings (cloudy urine, high specific gravity, dark amber color) to provider.

Provider Orders

Anticipate antibiotics if infection is confirmed, IV fluids if dehydration is severe.

Normal Blood Sugar (Fasting)

Should be ~70-110 mg/dL.

Hyperglycemia

Abnormally high blood glucose, e.g., 350 mg/dL.

Symptoms of Hyperglycemia

Assess for polyuria, polydipsia, polyphagia, blurred vision, fatigue.

Complications of Hyperglycemia

Monitor for dehydration, electrolyte imbalance, DKA (especially if Type 1), or HHS in Type 2.

Hypoglycemia

Abnormally low blood glucose, e.g., 60 mg/dL.

Symptoms of Hypoglycemia

Assess for shakiness, sweating, confusion, headache, irritability, palpitations, blurred vision, seizures if severe.

Hypoglycemia Protocol

Give 15 g fast-acting carbohydrate if conscious; administer IV dextrose or IM glucagon if unconscious.

Rule of 15

Recheck blood sugar in 15 minutes after treating hypoglycemia.

Patient Education on Hypoglycemia

Educate about meal timing, insulin administration, and recognizing early hypoglycemia signs.

HCT Level

58% indicates hemoconcentration (normal for male 42-52%, female 36-48).

Urine Specific Gravity

1.040 indicates very concentrated urine (normal 1.005-1.025).

Urine Color

Dark amber indicates concentrated urine.

Urine Output

Decreased urine output is referred to as oliguria.

Dehydration

Condition characterized by ↑ HCT, ↑ specific gravity, dark urine, and low output.

Hydration status monitoring

Assess skin turgor, mucous membranes, daily weights, intake/output.

Oral fluids encouragement

Encourage oral fluids if not contraindicated; anticipate IV fluid replacement if severe.

Vital signs monitoring

Monitor blood pressure and heart rate; tachycardia and hypotension can signal worsening dehydration.

Lab monitoring

Monitor electrolytes, BUN/creatinine to assess renal perfusion.

Patient safety precautions

Implement fall precautions if patient is dizzy/orthostatic.

Reporting findings

Report findings promptly to provider, as severe dehydration can lead to hypovolemia and shock if untreated.

Creatinine normal value

M: 0.9-1.3 mg/dL, F: 0.6-1.1 mg/dL; often remains 'normal' due to ↓ muscle mass.

BUN normal value

6-20 mg/dL; often increases reflecting ↓ renal function or dehydration.

Hematocrit (Hct) normal value

M: 42-52%, F: 36-48%; may be slightly lower as anemia is more common with age.

Hemoglobin (Hgb) normal value

M: 14-17.4 g/dL, F: 12-16 g/dL; may be slightly lower due to chronic illness or nutritional deficiency.

RBC normal value

M: 4.2-5.4 million/mm³, F: 3.6-5.0 million/mm³; decreases mildly as bone marrow activity slows.

WBC normal value

4,500-10,500/mm³; lower or blunted response may occur, infection may present without leukocytosis.

Urine Specific Gravity normal value

1.005-1.025; decreases as kidneys are less able to concentrate urine.

Summary of dehydration indicators

↑ HCT + ↑ SG + dark, low urine = dehydration.

Nursing focus

Hydrate, Monitor, Report, Prevent complications.

Cystoscopy

Assist provider; monitor sedation; maintain sterile technique.

Cystoscopy Post-Test Care

Monitor urine output; expect burning and pink-tinged urine; encourage fluids; watch for infection (fever, chills, dysuria).

Cystoscopy Pre-Test Care

Obtain consent; explain procedure; NPO if sedation used; may require bowel prep; baseline vitals.

Colonoscopy

Informed consent; clear liquid diet 24 hours before; bowel prep with laxatives; NPO after midnight.

Colonoscopy During Test Care

Assist with positioning and monitor recovery from sedation; observe for perforation (pain, bleeding, fever); resume diet when alert.

EGD (Esophagogastroduodenoscopy)

Informed consent; NPO 6-8 hours before; remove dentures; baseline vitals.

EGD During Test Care

Assist with sedation; monitor airway and vitals.

EGD Post-Test Care

Keep NPO until gag reflex returns; monitor for bleeding (black stools, hematemesis, pain).

Bronchoscopy

Assist provider; monitor sedation and O₂.

Bronchoscopy Pre-Test Care

Informed consent; NPO 6-8 hours; remove dentures; baseline vitals; explain procedure.

Bronchoscopy Post-Test Care

NPO until gag reflex returns; monitor for laryngeal edema, stridor, hemoptysis, respiratory distress.

CT Scan

Patient lies still; IV contrast may be given.

CT Scan Post-Test Care

Encourage fluids to flush contrast; monitor for reaction to dye.

CT Scan Pre-Test Care

Informed consent if contrast used; check allergies to iodine/shellfish; may require NPO; explain procedure.

MRI

Patient lies still in scanner; may need sedation for claustrophobia.

MRI Post-Test Care

Monitor for reaction to contrast if used; provide support for anxiety/claustrophobia.

MRI Pre-Test Care

Screen for metal implants, pacemaker, jewelry; explain procedure (loud noise, confined space); obtain consent.

Upper GI (Barium Swallow)

NPO after midnight; explain that barium is chalky-tasting.

Upper GI (Barium Swallow) During Test Care

Patient drinks barium contrast while X-rays are taken.

Upper GI (Barium Swallow) Post-Test Care

Encourage fluids; monitor stools (chalky/white is normal); give laxative if ordered to prevent impaction.