Lab data interpretation in pediatrics
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This document provides an overview of how to interpret various laboratory tests, including: - Growth charts to assess growth and development - Complete blood counts to evaluate indicators of anemia and hemolytic conditions - Blood gases to diagnose acid-base imbalances - Renal and liver function tests to identify organ dysfunction - Urine analysis and cerebrospinal fluid analysis to detect infections or other abnormalities It also reviews how to properly write a prescription, including listing the medication, dose, route, frequency, and duration. The goal is to help clinicians effectively evaluate and treat patients based on lab data.
Lab data interpretation in pediatrics
- 1. Lab data interpretation Presented by: Dr. Monther Alshahrani Saudi Board in Pediatric Medicine
- 2. Objectives Introduction Interpreting growth charts Interpretation of: Complete blood count Blood gas Renal function Liver function Urine analysis CSF analysis Writing a prescription
- 3. Introduction Laboratory tests help determine the presence, extent or absence of disease and monitor the effectiveness of treatment.
- 11. Physiological nadir In term infants: Decrease in hemoglobin noticed at 8-12 weeks of age (Hb 11 g/dL). In premature infants: Decrease in hemoglobin noticed at 6 weeks of age (Hb 7-10 g/dL).
- 13. Approach to anemia MCV LOW Iron deficiency Thalassemi a Sideroblastic anemia Anemia of chronic disease NORMAL Reticulocyte count Low or normal Infections Drugs Lead poisoning Acute blood loss Anemia of chronic disease Renal disease TEC High Evidence of hemolysis Yes Membranopathy Enzymopathy Hemoglobinopa thy Autoimmune Microangiopathic hemolytic anemia No Hemorrhage HIGH Drugs Vit B12/Folate def. Liver disease Hypothyrod ism Post splenectom y
- 14. Anemia with low MCV Iron deficiency Thalassemia Sideroblastic anemia Anemia of chronic disease
- 16. Anemia with normal MCV Reticulocyte count Low or normal Infections Drugs Lead poisoning Acute blood loss Anemia of chronic disease Renal disease TEC High Evidence of hemolysis Yes Membranop athy Enzymopathy Hemoglobinop athy Autoimmune Microangiop athic hemolytic anemia No Hemorrhage
- 17. Anemia with normal MCV and high reticulocyte Membranopathy Enzymopathy Hemoglobinopathy Autoimmune Microangiopathic hemolytic anemia Hemorrhage
- 19. Anemia with high MCV Drugs Vit B12/Folate deficiency Liver disease Hypothyrodism Post splenectomy
- 22. How to read a blood gas 1st look at pH Normal, borderline normal or abnormal High: alkalosis, low: acidosis Then PaCO2 with pH (metabolic), against pH (respiratory) High: acidosis, low: alkalosis Then HCO3 High: alkalosis, low: acidosis
- 23. Example pH 7.38 PaCO2 45 HCO3 24
- 24. Example pH 7.37 PaCO2 54 HCO3 24
- 25. Example pH 7.50 PaCO2 25 HCO3 16
- 26. Example pH 7.25 PaCO2 26 HCO3 15
- 27. Anion gap Serum anion gap = Measured cations - Measured anions Serum anion gap = (Na + K) - (Cl + HCO3) High anion gap > 12*
- 30. Example pH 7.52 PaCO2 53 HCO3 30
- 33. High urea and normal creatinine prerenal azotemia High protien diet High urea and creatinine Renal causes (impaired renal function)
- 38. Cholestasis or not? It is considered elevated if it is greater than 1.0 mg/dL (17.1 micromol/L) if the total serum bilirubin is <5.0 mg/dL (85.5 micromol/L). Or greater than 20 percent of the total serum bilirubin if the total serum bilirubin is >5.0 mg/dL (85.5 micromol/L).
- 39. Causes of cholestasis Extrahepatic obstruction Infection Metabolic/genetic diseases Endocrine Others
- 41. Gross visual examination Color – Yellow (light to deep amber) Clarity/turbidity – Clear or cloudy
- 42. Chemical examination/urine dipstick pH – 4.5-8 Specific gravity – 1.005-1.025 Glucose - ≤130 mg/d Ketones – None Nitrites – Negative Leukocyte esterase – Negative Bilirubin – Negative Urobilirubin – Small amount (0.5-1 mg/dL) Blood - ≤3 RBCs Protein - ≤150 mg/d
- 43. Microscopic examination/urine sediment RBCs - ≤2 RBCs/hpf WBCs - ≤2-5 WBCs/hpf Squamous epithelial cells - ≤15-20 squamous epithelial cells/hpf Casts – 0-5 hyaline casts/lpf Crystals – Occasionally Bacteria – None Yeast - None
- 44. Sensitivity and specificity of: Nitrites and Leukocyte esterase Leukocyte esterase Nitrites
- 46. Slightly highSignificantly high Note: Usually TB meningitis associated with other findings in the history suggestive for it (history of travel to endemic area, contact or prolonged fever, etc.)
- 47. WBC in CSF Neonate Preterm less than 30 Term less than 20 Infant less than 10 Child less than 7
- 48. How to write a prescription
- 49. How to write a prescription Medication generic name Type Dose Route Interval Duration Note: calculate the dose/kg/day, never write the dose in (ml) unless you write the concentration.
- 50. Example You want to write acetaminophen and amoxicillin for 5 years old boy, his weight is 20 kg. Acetaminophen dose 15mg/kg/dose Amoxicillin dose 25-45mg/kg/day divided BID or TID
- 51. Acetaminophen 15 X 20 = 300 mg Acetaminophen syrup 300 mg PO every 6 hours PRN Amoxicillin 40 X 20 = 800 mg /day 800/2 = 400 mg /dose Amoxicillin syrup 400mg PO BID for 7 days
- 53. Thank you
Editor's Notes
- #6: normal
- #7: Failure to thrive (crossing two centiles)
- #8: Failure to growth (less than 3rd centile)
- #10: What are the causes of leukocytosis?
- #12: Erythropoiesis decreases dramatically after birth as a result of increased tissue oxygenation and a reduced production of erythropoietin.
- #25: compensated respiratory acidosis Respiratory acidosis caused by hypoventilation
- #26: uncompensated respiratory alkalosis Pneumonia Pulmonary Embolism Congestive Heart Failure Hepatic Insufficiency Sepsis Peritonitis
- #27: uncompensated metabolic acidosis High anion gap causes? Normal anion gap causes?
- #28: *the normal range anion gap for each of the individual measurements varies depending upon the specific analyzer utilized.
- #31: uncompensated metabolic alkalosis causes?