Ordering and Interpreting Laboratory Values

Resident Orientation

Outline

• Lab Structure• Available Tests at NMH• Ordering tests at NMH

– Collection– Ordering– Results – Cost

• Critical Values

Laboratory Structure

• Inpatient Hospital Lab

• Transfusion Services

• Outpatient Poly Clinic Laboratory

• Blood Donor Center

Laboratory Hours

• Normal Working Hours– Saturday – Wednesday:

0800 – 1500– Thursday: 0800 – 1200

• Duty Hours– Saturday – Wednesday:

1500 – 0800– Thursday: 1200 – 0800– Friday 0800 – 0800

Laboratory Contact Information• Inpatient Hospital

– Biochemistry 261-6683– Hematology 261-6693– Laboratory Chief 261-3224

• Blood Bank – 261-6682

• Outpatient Poly Clinic– Bacteriology 261-3187– Biochemistry 261-6659– Lab Director 261-3170

• Blood Donor Center– 261-6682

Available Tests at NMH

• Chem 7• Complete Blood Count

(CBC)• Urinalysis (UA)• Cultures

– Blood– Urine– Wound

Available Tests at NMH

• Malaria– Rapid Test– Smear

• Rapid TB• Serology

– H. pylori– Rheumatoid Factor– Hepatitis B and C– Syphilis– Febrile Antigen

Available Tests at NMH

• iSTAT– PT– Troponin I– Arterial Blood Gas

• Cholesterol and Triglycerides

• Blood Bank– Whole Blood– ABO testing– Rh testing

Indications for Ordering a CBC

• Concern for infection

• Concern for anemia

• Bleeding– Platelets

• To investigate hematological cancer– Leukemia

Indications for Ordering a Chemistry Panel

• Evaluate Electrolytes– Sodium– Potassium– Chloride– Calcium

• Evaluate Renal Function– BUN– Creatinine

• Diagnosis of Diabetes– Glucose

Indications for Ordering a Urinalysis

• Concern for a Urinary Tract Infection– White Blood Cells

• Concern for Diabetes– Glucose

• Evaluation of Renal Function– Albumin– RBCs

• Evaluation of Stone Disease– Crystals– RBCs

Specimen Collection Procedure

• Check patient’s identification

• Label specimen with patient’s name

• Transport specimen with order form

• Routine laboratory results are available daily after 1 pm

Collection• Red Top Tube

– Chem 7– Serology– Cross-match

• Blue Top Tube– Coagulation Studies

• Lavender Top Tube– CBC– Cross-match

Specimen Rejection

• Mismatched specimen requisition

• Improperly collected specimen

• Unlabeled specimen• Specimens without

requisitions• Contaminated specimen

or requisition

Test Priorities

• Tests will be run based on priority.

• Must specify priority when ordering test– Routine: 24 hours

– ASAP: 4 hours

– STAT: 1 hour

Priority اولیت زمان Expected TAT حقشده توقوع

ROUTINE24 روتین hours 24 ساعت

ASAP ممکن زودتر هرچه باشد

4 hours4 ساعت

STAT1 عاجل hour ساعت یک

Laboratory Costs• Chemistry

– 1000 Afghani

• Complete Blood Count– 120 Afghani

• Culture– 320 Afghani

• Cholesterol Panel– 550 Afghani

• Urinalysis– 6 Afghani

• Order only what you need, DO NOT WASTE MONEY

Results: Chemistry

• Chemistry Results will be prepared on a lab result paper and delivered to the ordering doctor

Results: CBC

• CBC results will be reported on this laboratory document and given to the physician

Results: Bacterial Sensitivities• After an organism grows

in a culture, the laboratory will automatically check the effectiveness of antibiotics on the bacteria

Results: Serology

• Serologic Tests will be reported on this laboratory sheet and given to the ordering doctor

Interpreting a Chemistry Panel• Sodium

– Normal: 136-145 mmol/l– Hypernatremia (> 145)

• Dehydration

– Hyponatremia (<136)• SIADH• Heart Failure• Medications

• Potassium– Normal: 3.5-5.2 mmol/l– Hyperkalemia (> 5.2)

• Renal Failure• Hyperaldosteronism• Medications

– Hypokalemia (< 3.5)• Vomiting / Diarrhea• Medications

Interpreting a Chemistry Panel• BUN

– Normal 15-50 mg/dl– > 50

• Renal Failure• Dehydration

– < 15• Malnutrition• Chronic Inflammation Syndromes

• Creatinine– Normal: 0.5-1.0 mg/dl– > 1.0

• Renal Failure• Dehydration

– < 0.5• Malnutrition• Decreased muscle mass

Interpreting a CBC• White Blood Cell

– Normal: 4000 – 10,000 cmm– < 4000

• Medications• Hematological Cancer

– > 10,000• Infection• Hematological cancer

• Hemoglobin– Normal 11.5-18.0 g/dl– > 18.0

• Hemochromatosis• Polycythemia Vera

– < 11.5• Anemia: disorder in production,

increased destruction, or bleeding

Interpreting a CBC

• Hematocrit (HCT)– Normal: 39-49%– > 49%– < 39%

• Platelets– Normal: 150,000-400,000

cmm– > 400,000

• Normal response to illness or inflammation

– < 150,000• Burns• Bone Marrow Disorders

Critical Values

• Lab results that are life threatening

• The laboratory Department Head will be notified

• Ordering physician will be notified

• As a resident, you should notify your instructor or staff physician

Critical Values: HematologyHEMATOLOGY

الوژی ت هم

TEST

آزمايش

VALUE LESS THAN

از كمتر مقدار

VALUE MORE THAN

از بیشتر مقدار

Prothrombin Time

خون ) ( علقه زمان تایم پروترومبیتN/A نیست دریافت seconds 30 قابل

WBC Count

خون سفيد حجرات تعداد

2,000/cumm 25,000/cumm

Hemoglobin

موگلوبينیه

7.0 g/dl 20.0 g/dl

Hematocrit

هماتوكريت

21.0% 50.0%

Platelet Count

دمویه صفحیات تعداد

50,000/cumm 1,000,000/cumm

Blood smear

خون سمير

Presence of immature WBC’s, immature RBC’s or malaria parasites.

ویا RBC’sنارس، WBC’s موجوديت نارسمالريا های پرازيت

Critical Values: ChemistryCHEMISTRYبیوشیمی

TEST

ازمايش

VALUE LESS THAN

از كمتر مقدار

VALUE MORE THAN

از بیشتر مقدار

Chloride, serum or plasma

پالزما یا كلورايد،سيروم

80 mmol/l 110 mmol/l

Creatinine, serum or plasma

پالزما یا سيروم كرياتينين،

N/A 5.0 mg/dl

Sodium, serum or plasma

پالزما یا سيروم ، سوديم

125 mmol/l 150 mmol/l

Critical Values: Chemistry ContinuedCHEMISTRYبیوشیمی

TEST

ازمايش

VALUE LESS THAN

از كمتر مقدار

VALUE MORE THAN

از بیشتر مقدار

Potassium, serum or plasma

یاپالزما پوتاشيم،سيروم

2.8 mmol/l 6.0 mmol/l

Glucose, serum or plasma

پالزما یا گلوكوز،سيروم

50 mg/dl 350 mg/dl

Ionized calcium, plasma

پالزما شده، ايونايز كلسيم

3.0 mg/dl 6.4 mg/dl

Urea nitrogen, serum or plasma

يوريانايتروجن،سيروم یاپالزما

N/A 80 mg/dl

Critical Values: UrinalysisURINALYSIS

ادرار معاينات

TEST

ازمايشVALUE LESS THAN

از كمتر مقدارVALUE MORE

THAN

از بیشتر مقدار

Glucose

گلوكوز

N/A >1000 mg/dl

Microscopic

مايكروسكوپيك N/APresence of pathological crystals )urate, cysteine, leucine, or tyrosine(

هاي كريستال موجوديتيورات،سيستين) ،پتالوژيك

تايروسين و (ليوسين

Ketones, urine/serum

/ سیروم ،ادرار ها كيتون

N/A نیست دریافت زیاد)mg/dl )Large 80< قابل

Critical Values: Arterial Blood GasARTERIAL BLOOD GASES

شيرياني خون گازهاي

TEST

آزمايشVALUE LESS THAN

از كمتر مقدارVALUE MORE THAN

از مقداربیشتر

pH, arterial, capillary

، شعریه عروق ، pH شيرياني

7.20 7.60

pCO2, arterial, capillary

اکساید،شریانی دای فشارکاربنوی شعریه ،

20 mm/Hg 70 mm/Hg

pO2, arterial

اکسیجن فشار شيرياني

40 mm/Hg N/A نیست دریافت قابل

Critical Values: Microbiology

MICROBIOLOGYمايكروبيولوژي

TEST آزمايش

VALUE LESS THANاز كمتر مقدار

VALUE MORE THANاز بیشتر مقدار

Blood Cultures

خون كلچرهای

N/A نیست دریافت Positive قابل

مثبت

Point of Care Testing

• Diagnostic testing at or near the site of patient care

• Available in– ICU– Internal medicine

• Available tests– Chemistry 8– Arterial Blood Gas– PT/INR

Conclusions

• The laboratory can provide valuable information to help diagnose and treat patients.

• Always take cost into consideration when ordering a test

• Learning to properly interpret lab results is essential for residents