CMP BMP + Ca, Albumin/total protein, LFTs

Albumin - 3.4-5.4 g/dL

• Hyperalbuminemia - Dehydration

• Hypoalbuminemia - Cirrhosis, nephrotic syndrome, inflammation, malnutrition

Calcium - 8-10 mg/dL (bound) or 4.0-5.6 (ionized)

• Hypocalcemia

  • with ↓ PTH - 1 ° HypoPTH (post-surgical or autoimmune)

  • with ↑ PTH - vit D deficiency

  • PsuedohypoPTH/hyperphosphatemia (↑ PO4)

  • CKD (↑ PO4, ↑ creatinine) Malabsorption (↓ Mg)

• Hypercalcemia 

  • with ↓ PTH - vit D intoxication

  • with ↑ PTH - 1 ° hyperPTH (↓ PO4); ↑ urine Ca

Ca is a cation and binds negatively charged albumin 

• If there is less albumin... there is "less" bound Ca ➔ false lower Ca level 

• In other words, in hypoalbuminemia, there is more Ca present than measured 

  • Use corrected calcium (or ionized Ca) if albumin < 4.0:  [Ca] + 0.8(4.0 - albumin)

Amylase/Lipase

• Acute pancreatitis ➔ ↑ more than 3x 

  • Lipase more pancreas specific than amylase

• Can go up with gallbladder

• Amylase can ↑ with  salivary gland problems

• Renal failure ➔ ↑ (↓ excretion)

Elastase

• Acute pancreatitis ➔ ↑ in serum  

• Exocrine pancreatic insufficiency (cystic fibrosis, chronic pancreatitis)  ➔ ↓ in stool 

• Color

• Clarity

• pH: 4.5–8

• Urine specific gravity: urine density/pure water density (normally 1.005–1.030) 

  • 1.010-1.030 hints at dehydration

  • High specific gravity: (more concentrated) volume loss, HF, glucose or radiocontrast in urine

  • Low specific gravity: (dilute) renal failure, DI

• Heme: hematuria dx requires microscopy

  • Semen, myoglobin ➔ positive

  • Vit. C in urine can ➔ false negative 

• Leukocyte esterase: hints at UTI

• Protein: picks up gross albumin, not nephrotoxic light chain IG (like Bence Jones protein)

• Glucose: DM ➔ glycosuria 

• Ketones: DKA

• Urobilinogen: 

  • No urobilinogen in urine of jaundiced pt: complete biliary obstruction

  • Increased urobilinogen:  hemolysis, cirrhosis, hepatitis

• Nitrite: UTI with gram neg bx MC Enterobacteriaceae 

Sediment

• RBC and WBC

• Casts

  • Can be normal finding or sign of serious renal issue

  • Casts assume shape and size of renal tubule where they are formed

    • Hyaline casts - Nonspecific (CKD) or intense exercise

    • Granular cast - Acute tubular necrosis, pyelonephritis

    • Muddy brown casts - Acute tubular necrosis

    • Hemoglobin casts - Intravascular hemolysis

    • Fatty casts - Nephrotic syndrome

    • Renal tubular epithelial cell casts - Interstitial nephritis, proliferative glomerulonephritis

    • White blood cell casts -  pyelonephritis

    • Red blood cell casts - glomerulonephritis

    • Waxy casts - Nonspecific AKD/CKD

Urine Culture

• ASX pt:  ≥10^5 CFU/mL

• SX ♀ with pyuria ≥10^2/mL: indicative of a UTI 

hCG

 Human chorionic gonadotropin

• β-hCG is placenta specific

  • Urine hCG: ~ 14d after fertilization

  • Serum hCG: ~ 6-9d after fertilization

• Doubles every 2d first month, peaks at ~10-12wks

• Embryo visible at 1,500-2000 (~5-6wks) and cardiac activity

• Doppler US detects fetal heartbeat (~10-12wks)

Cancer markers

Alphafetoprotein (AFP)

• Liver, Testes, Ovarian

• Produced by developing fetus liver

• ↑ in pregnancy and birth (↓ by 1yo)

• Produced when liver cells regenerate

• Hepatocellular carcinoma dx or monitor tx/recurrence

• ↑ in cirrhosis, hepatitis

CA 125

• Ovarian/gynecologic, lymphoma

• Good for following TX

CA 19-9

• Pancreatic cancer

FIT/FOBT

• Stool sample for occult blood (colorectal cancer) or R/O anemia

• Screening: Annually at 50yo (40yo if 1st ° relative hx)

• Get colonoscopy if positive (after r/o hemorrhoids)

  • Can see "apple core lesion" on double barium

  • CEA for monitoring/not screening

Autoimmune

ANA (Anti-Nuclear-AB)

Autoimmune affecting connective tissue

• Anti-dsDNA ➔ SLE (with anti-phospholipid)

• Anti-RO/LA ➔ Sjögren (with RF)

• Anti-Joa/Mi2 ➔ Polymyositis (with RF)

ANCA (Anti-Neutrophil Cytoplasmic AB)

Autoimmune ➔ Vasculitis, GI, Hepatic

• c-ANCA ➔ Granulomatosis with polyangitis

• p-ANCA ➔ Microscopic polyangitis

• Atypical p-ANCA ➔ Primary sclerosing cholangitis, ulcerative colitis